1.6.1

.gitea/workflows/default_tags.yaml

@@ -119,6 +119,6 @@ jobs:
         run: |
           npmci node install stable
           npmci npm install
-          pnpm install -g @gitzone/tsdoc
+          pnpm install -g @git.zone/tsdoc
           npmci command tsdoc
         continue-on-error: true

changelog.md

@@ -1,5 +1,52 @@
 # Changelog
 
+## 2025-03-04 - 1.6.1 - fix(build)
+Corrected package.json and workflow dependencies and resolved formatting issues in tests.
+
+- Fixed incorrect global npm package reference for tsdoc installation in workflow file.
+- Updated dependencies in package.json for consistency in package naming.
+- Resolved inconsistent formatting and spacing in test files.
+
+## 2025-03-04 - 1.6.0 - feat(assertion)
+Enhanced the assertion error messaging and added new test cases.
+
+- Improved error messages by incorporating path and value/placeholders in assertions.
+- Added detailed testing of new assertion functionalities.
+- Additional test cases for comprehensive coverage of new features.
+
+## 2025-03-04 - 1.5.0 - feat(Assertion)
+Add toBeTypeOf assertion method
+
+- Introduced a new assertion method `toBeTypeOf` allowing checks for expected data types.
+- Updated devDependencies and dependencies to their latest versions.
+
+## 2024-12-30 - 1.4.0 - feat(Assertion)
+Add log method to Assertion class
+
+- Introduced a log method in the Assertion class to output assertion context.
+
+## 2024-12-30 - 1.3.0 - feat(Assertion)
+Refactor Assertion class for better error handling and code clarity
+
+- Improved method runCheck to better handle async and sync execution
+- Enhanced getObjectToTestReference to handle undefined or null values gracefully
+- Refactored error message logic for clarity and added more descriptive fail messages
+- Added arrayItem method for better handling of array index access
+- Improved structure by integrating consistent error handling in assertion methods
+
+## 2024-08-24 - 1.2.1 - fix(Assertion)
+Refactor methods for setting failure and success messages
+
+- Renamed 'withFailMessage' to 'setFailMessage' for better readability and consistency.
+- Renamed 'withSuccessMessage' to 'setSuccessMessage' to align with the naming convention.
+
+## 2024-08-24 - 1.2.0 - feat(assertions)
+Add custom fail and success messages for assertions
+
+- Implemented withFailMessage method in Assertion class to customize fail messages
+- Implemented withSuccessMessage method in Assertion class to customize success messages
+- Enhanced error messages to use custom fail messages when provided
+
 ## 2024-08-17 - 1.1.0 - feat(assertion)
 Add toBeDefined assertion method
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@push.rocks/smartexpect",
-  "version": "1.1.0",
+  "version": "1.6.1",
   "private": false,
   "description": "A testing library to manage expectations in code, offering both synchronous and asynchronous assertion methods.",
   "main": "dist_ts/index.js",
@@ -10,20 +10,20 @@
   "license": "MIT",
   "scripts": {
     "test": "(tstest test/ --web)",
-    "build": "(tsbuild --web)",
+    "build": "(tsbuild tsfolders)",
     "buildDocs": "tsdoc"
   },
   "devDependencies": {
-    "@gitzone/tsbuild": "^2.1.66",
-    "@gitzone/tsbundle": "^2.0.8",
-    "@gitzone/tsrun": "^1.2.44",
-    "@gitzone/tstest": "^1.0.77",
-    "@push.rocks/tapbundle": "^5.0.23",
-    "@types/node": "^22.4.0"
+    "@git.zone/tsbuild": "^2.2.1",
+    "@git.zone/tsbundle": "^2.2.5",
+    "@git.zone/tsrun": "^1.3.3",
+    "@git.zone/tstest": "^1.0.96",
+    "@push.rocks/tapbundle": "^5.5.6",
+    "@types/node": "^22.13.9"
   },
   "dependencies": {
     "@push.rocks/smartdelay": "^3.0.5",
-    "@push.rocks/smartpromise": "^4.0.4",
+    "@push.rocks/smartpromise": "^4.2.3",
     "fast-deep-equal": "^3.1.3"
   },
   "browserslist": [
@@ -57,5 +57,10 @@
   "repository": {
     "type": "git",
     "url": "https://code.foss.global/push.rocks/smartexpect.git"
+  },
+  "pnpm": {
+    "onlyBuiltDependencies": [
+      "mongodb-memory-server"
+    ]
   }
 }

readme.md

@@ -1,5 +1,5 @@
 # @push.rocks/smartexpect
-manage expectations in code
+Manage expectations in code with precise, readable assertions
 
 ## Install
 
@@ -30,14 +30,16 @@ You can employ `expect` to create synchronous assertions:
 ```typescript
 import { expect } from '@push.rocks/smartexpect';
 
-// String type assertion
+// Type assertions
 expect('hello').toBeTypeofString();
-
-// Negated String type assertion
-expect(1).not.toBeTypeofString();
-
-// Boolean type assertion
+expect(42).toBeTypeofNumber();
 expect(true).toBeTypeofBoolean();
+expect(() => {}).toBeTypeOf('function');
+expect({}).toBeTypeOf('object');
+
+// Negated assertions
+expect(1).not.toBeTypeofString();
+expect('string').not.toBeTypeofNumber();
 
 // Equality assertion
 expect('hithere').toEqual('hithere');
@@ -61,68 +63,184 @@ const asyncStringFetcher = async (): Promise<string> => {
 };
 
 const asyncTest = async () => {
-  await expectAsync(asyncStringFetcher()).toBeTypeofString();
+  // Add a timeout to prevent hanging tests
+  await expectAsync(asyncStringFetcher()).timeout(5000).toBeTypeofString();
   await expectAsync(asyncStringFetcher()).toEqual('async string');
 };
 
 asyncTest();
 ```
 
-### Advanced Usage
+### Navigating Complex Objects
 
-- **Properties and Deep Properties:** Assert the existence of properties and their values.
-  
-  ```typescript
-  const testObject = { level1: { level2: 'value' } };
+You can navigate complex objects using the `property()` and `arrayItem()` methods:
 
-  // Property existence
-  expect(testObject).toHaveProperty('level1');
-  
-  // Deep Property existence
-  expect(testObject).toHaveDeepProperty(['level1', 'level2']);
-  ```
+```typescript
+const complexObject = {
+  users: [
+    { id: 1, name: 'Alice', permissions: { admin: true } },
+    { id: 2, name: 'Bob', permissions: { admin: false } }
+  ]
+};
 
-- **Conditions and Comparisons:** Allow more intricate assertions like greater than, less than, or matching specific conditions.
+// Navigate to a nested property
+expect(complexObject)
+  .property('users')
+  .arrayItem(0)
+  .property('name')
+  .toEqual('Alice');
 
-  ```typescript
-  // Greater Than
-  expect(5).toBeGreaterThan(3);
+// Check nested permission
+expect(complexObject)
+  .property('users')
+  .arrayItem(0)
+  .property('permissions')
+  .property('admin')
+  .toBeTrue();
+```
 
-  // Less Than
-  expect(3).toBeLessThan(5);
+### Advanced Assertions
 
-  // Custom conditions
-  expect(7).customAssertion(value => value > 5, 'Value is not greater than 5');
-  ```
+#### Properties and Deep Properties
 
-- **Arrays and Objects:** Work seamlessly with arrays and objects, checking for containment, length, or specific values.
+Assert the existence of properties and their values:
 
-  ```typescript
-  const testArray = [1, 2, 3];
+```typescript
+const testObject = { level1: { level2: 'value' } };
 
-  // Containment
-  expect(testArray).toContain(2);
+// Property existence
+expect(testObject).toHaveProperty('level1');
 
-  // Array length
-  expect(testArray).toHaveLength(3);
+// Property with specific value
+expect(testObject).toHaveProperty('level1.level2', 'value');
 
-  // Object matching
-  expect({ name: 'Test', value: 123 }).toMatchObject({ name: 'Test' });
-  ```
+// Deep Property existence
+expect(testObject).toHaveDeepProperty(['level1', 'level2']);
+```
 
-### Handling Promises and Async Operations
+#### Conditions and Comparisons
 
-`@push.rocks/smartexpect` gracefully integrates with asynchronous operations, providing a `expectAsync` function that handles promise-based assertions. This keeps your tests clean and readable, irrespective of the nature of the code being tested.
+Perform more intricate assertions:
 
-### Best Practices
+```typescript
+// Numeric comparisons
+expect(5).toBeGreaterThan(3);
+expect(3).toBeLessThan(5);
+expect(5).toBeGreaterThanOrEqual(5);
+expect(5).toBeLessThanOrEqual(5);
+expect(0.1 + 0.2).toBeCloseTo(0.3, 10); // Floating point comparison with precision
 
-- **Readability:** Favor clarity and readability by explicitly stating your expectations. `@push.rocks/smartexpect`'s API is designed to be fluent and expressive, making your tests easy to write and, more importantly, easy to read.
+// Truthiness checks
+expect(true).toBeTrue();
+expect(false).toBeFalse();
+expect('non-empty').toBeTruthy();
+expect(0).toBeFalsy();
 
-- **Comprehensive Coverage:** Utilize the full spectrum of assertions provided to cover a broad set of use cases, ensuring your code behaves as expected not just in ideal conditions but across various edge cases.
+// Null/Undefined checks
+expect(null).toBeNull();
+expect(undefined).toBeUndefined();
+expect(null).toBeNullOrUndefined();
 
-- **Maintainability:** Group related assertions together to improve test maintainability. This makes it easier to update tests as your codebase evolves.
+// Custom conditions
+expect(7).customAssertion(value => value % 2 === 1, 'Value is not odd');
+```
 
-Through judicious use of `@push.rocks/smartexpect`, you can enhance the reliability and maintainability of your test suite, making your codebase more robust and your development workflow more efficient.
+#### Arrays and Collections
+
+Work seamlessly with arrays and collections:
+
+```typescript
+const testArray = [1, 2, 3];
+
+// Array checks
+expect(testArray).toBeArray();
+expect(testArray).toHaveLength(3);
+expect(testArray).toContain(2);
+expect(testArray).toContainAll([1, 3]);
+expect(testArray).toExclude(4);
+expect([]).toBeEmptyArray();
+expect(testArray).toHaveLengthGreaterThan(2);
+expect(testArray).toHaveLengthLessThan(4);
+
+// Deep equality in arrays
+expect([{ id: 1 }, { id: 2 }]).toContainEqual({ id: 1 });
+```
+
+#### Strings
+
+String-specific checks:
+
+```typescript
+expect('hello world').toStartWith('hello');
+expect('hello world').toEndWith('world');
+expect('hello world').toInclude('lo wo');
+expect('options').toBeOneOf(['choices', 'options', 'alternatives']);
+```
+
+#### Functions and Exceptions
+
+Test function behavior and exceptions:
+
+```typescript
+const throwingFn = () => { throw new Error('test error'); };
+expect(throwingFn).toThrow();
+expect(throwingFn).toThrow(Error);
+
+const safeFn = () => 'result';
+expect(safeFn).not.toThrow();
+```
+
+#### Date Assertions
+
+Work with dates:
+
+```typescript
+const now = new Date();
+const past = new Date(Date.now() - 10000);
+const future = new Date(Date.now() + 10000);
+
+expect(now).toBeDate();
+expect(now).toBeAfterDate(past);
+expect(now).toBeBeforeDate(future);
+```
+
+### Debugging Assertions
+
+The `log()` method is useful for debugging complex assertions:
+
+```typescript
+expect(complexObject)
+  .property('users')
+  .log() // Logs the current value in the assertion chain
+  .arrayItem(0)
+  .log() // Logs the first user
+  .property('permissions')
+  .log() // Logs the permissions object
+  .property('admin')
+  .toBeTrue();
+```
+
+### Customizing Error Messages
+
+You can provide custom error messages for more meaningful test failures:
+
+```typescript
+expect(user.age)
+  .setFailMessage('User age must be at least 18 for adult content')
+  .toBeGreaterThanOrEqual(18);
+```
+
+## Best Practices
+
+- **Human-readable assertions**: The fluent API is designed to create tests that read like natural language sentences.
+
+- **Precise error messages**: When tests fail, the error messages provide detailed information about what went wrong, including expected vs. actual values.
+
+- **Property path navigation**: Use the property path methods to navigate complex objects without creating temporary variables.
+
+- **Comprehensive testing**: Take advantage of the wide range of assertion methods to test various aspects of your code.
+
+- **Debugging with log()**: Use the `log()` method to see intermediate values in the assertion chain during test development.
 
 ## License and Legal Information
 
@@ -141,4 +259,4 @@ Registered at District court Bremen HRB 35230 HB, Germany
 
 For any legal inquiries or if you require further information, please contact us via email at hello@task.vc.
 
-By using this repository, you acknowledge that you have read this section, agree to comply with its terms, and understand that the licensing of the code does not imply endorsement by Task Venture Capital GmbH of any derivative works.
+By using this repository, you acknowledge that you have read this section, agree to comply with its terms, and understand that the licensing of the code does not imply endorsement by Task Venture Capital GmbH of any derivative works.

test/test.both.ts

@@ -0,0 +1,218 @@
+import { tap } from '@push.rocks/tapbundle';
+import * as smartexpect from '../ts/index.js';
+
+tap.test('basic type assertions', async () => {
+  // String type checks
+  smartexpect.expect('hello').toBeTypeofString();
+  smartexpect.expect(1).not.toBeTypeofString();
+
+  // Boolean type checks
+  smartexpect.expect(true).toBeTypeofBoolean();
+  smartexpect.expect(false).toBeTypeofBoolean();
+  smartexpect.expect(1).not.toBeTypeofBoolean();
+
+  // Number type checks
+  smartexpect.expect(42).toBeTypeofNumber();
+  smartexpect.expect(true).not.toBeTypeofNumber();
+
+  // Generic type checks with new method
+  smartexpect.expect(() => {}).toBeTypeOf('function');
+  smartexpect.expect(class Test {}).toBeTypeOf('function');
+  smartexpect.expect({}).toBeTypeOf('object');
+  smartexpect.expect(Symbol('test')).toBeTypeOf('symbol');
+});
+
+tap.test('async tests', async (toolsArg) => {
+  const deferred = toolsArg.defer();
+  toolsArg.delayFor(1000).then(() => {
+    deferred.resolve('hello');
+  });
+  await smartexpect.expectAsync(deferred.promise).timeout(2000).toBeTypeofString();
+  await smartexpect.expectAsync(deferred.promise).not.toBeTypeofBoolean();
+
+  // Test async timeout handling
+  const longOperation = toolsArg.defer();
+  toolsArg.delayFor(3000).then(() => {
+    longOperation.resolve('completed');
+  });
+  try {
+    await smartexpect.expectAsync(longOperation.promise).timeout(1000).toBeDefined();
+    throw new Error('Should have timed out');
+  } catch (err) {
+    // Expected timeout error
+    console.log('Successfully caught timeout:', err.message);
+  }
+});
+
+tap.test('equality and matching assertions', async () => {
+  // Basic equality
+  smartexpect.expect('hithere').toEqual('hithere');
+  smartexpect.expect('hithere').not.toEqual('hithere2');
+
+  // Object equality
+  const obj1 = { a: 1, b: { c: true } };
+  const obj2 = { a: 1, b: { c: true } };
+  const obj3 = { a: 1, b: { c: false } };
+  smartexpect.expect(obj1).toEqual(obj2);
+  smartexpect.expect(obj1).not.toEqual(obj3);
+
+  // RegExp matching
+  smartexpect.expect('hithere').toMatch(/hi/);
+  smartexpect.expect('hithere').toMatch(/^hithere$/);
+  smartexpect.expect('hithere').not.toMatch(/ho/);
+
+  // String inclusion
+  smartexpect.expect('hithere').toInclude('hit');
+  smartexpect.expect('hithere').not.toInclude('missing');
+
+  // String start/end
+  smartexpect.expect('hithere').toStartWith('hi');
+  smartexpect.expect('hithere').toEndWith('ere');
+});
+
+tap.test('object property assertions', async () => {
+  const testObject = {
+    topLevel: 'hello',
+    nested: {
+      prop: 42,
+      deeplyNested: {
+        array: [1, 2, 3],
+      },
+    },
+  };
+
+  // Basic property checks
+  smartexpect.expect(testObject).toHaveProperty('topLevel');
+  smartexpect.expect(testObject).toHaveProperty('topLevel', 'hello');
+  smartexpect.expect(testObject).not.toHaveProperty('missing');
+
+  // Drill-down property navigation
+  smartexpect.expect(testObject).property('nested').toHaveProperty('prop', 42);
+  smartexpect
+    .expect(testObject)
+    .property('nested')
+    .property('deeplyNested')
+    .property('array')
+    .toBeArray();
+
+  // Deep property checks
+  smartexpect.expect(testObject).toHaveDeepProperty(['nested', 'deeplyNested', 'array']);
+
+  // Array item navigation
+  smartexpect
+    .expect(testObject)
+    .property('nested')
+    .property('deeplyNested')
+    .property('array')
+    .arrayItem(0)
+    .toEqual(1);
+});
+
+tap.test('numeric comparison assertions', async () => {
+  // Greater/less than
+  smartexpect.expect(4).toBeGreaterThan(3);
+  smartexpect.expect(4).toBeLessThan(5);
+  smartexpect.expect(4).toBeGreaterThanOrEqual(4);
+  smartexpect.expect(4).toBeLessThanOrEqual(4);
+
+  // Approximate equality
+  smartexpect.expect(0.1 + 0.2).toBeCloseTo(0.3, 10);
+});
+
+tap.test('array assertions', async () => {
+  const obj1 = { id: 1 };
+  const obj2 = { id: 2 };
+  const testArray = [1, 'two', obj1, true];
+
+  // Basic array checks
+  smartexpect.expect(testArray).toBeArray();
+  smartexpect.expect(testArray).toHaveLength(4);
+
+  // Content checks
+  smartexpect.expect(testArray).toContain('two');
+  smartexpect.expect(testArray).toContain(obj1);
+  smartexpect.expect(testArray).not.toContain(obj2);
+
+  // Array with equal items (not same reference)
+  smartexpect.expect([{ a: 1 }, { b: 2 }]).toContainEqual({ a: 1 });
+
+  // Multiple values
+  smartexpect.expect(testArray).toContainAll([1, 'two']);
+  smartexpect.expect(testArray).toExclude('missing');
+
+  // Empty array
+  smartexpect.expect([]).toBeEmptyArray();
+
+  // Length comparisons
+  smartexpect.expect(testArray).toHaveLengthGreaterThan(3);
+  smartexpect.expect(testArray).toHaveLengthLessThan(5);
+});
+
+tap.test('boolean assertions', async () => {
+  // True/False
+  smartexpect.expect(true).toBeTrue();
+  smartexpect.expect(false).toBeFalse();
+
+  // Truthy/Falsy
+  smartexpect.expect('something').toBeTruthy();
+  smartexpect.expect(0).toBeFalsy();
+
+  // Null/Undefined
+  smartexpect.expect(null).toBeNull();
+  smartexpect.expect(undefined).toBeUndefined();
+  smartexpect.expect(null).toBeNullOrUndefined();
+  smartexpect.expect(undefined).toBeNullOrUndefined();
+});
+
+tap.test('function assertions', async () => {
+  // Function that throws
+  const throwingFn = () => {
+    throw new Error('test error');
+  };
+  smartexpect.expect(throwingFn).toThrow();
+  smartexpect.expect(throwingFn).toThrow(Error);
+
+  // Function that doesn't throw
+  const nonThrowingFn = () => 'safe';
+  smartexpect.expect(nonThrowingFn).not.toThrow();
+});
+
+tap.test('date assertions', async () => {
+  const now = new Date();
+  const past = new Date(Date.now() - 10000);
+  const future = new Date(Date.now() + 10000);
+
+  smartexpect.expect(now).toBeDate();
+  smartexpect.expect(now).toBeAfterDate(past);
+  smartexpect.expect(now).toBeBeforeDate(future);
+});
+
+tap.test('custom assertions', async () => {
+  // Custom validation logic
+  smartexpect.expect(42).customAssertion((value) => value % 2 === 0, 'Expected number to be even');
+
+  // With fail message
+  smartexpect.expect('test').setFailMessage('Custom fail message for assertion').toHaveLength(4);
+});
+
+tap.test('logging and debugging', async () => {
+  // Using log() for debugging
+  const complexObject = {
+    level1: {
+      level2: {
+        value: 'nested value',
+      },
+    },
+  };
+
+  // This logs the current value in the chain for debugging
+  smartexpect
+    .expect(complexObject)
+    .property('level1')
+    .property('level2')
+    .log()
+    .property('value')
+    .toEqual('nested value');
+});
+
+export default tap.start();

test/test.ts

@@ -1,52 +0,0 @@
-import { tap } from '@push.rocks/tapbundle';
-import * as smartexpect from '../ts/index.js';
-
-tap.test('sync tests', async () => {
-  smartexpect.expect('hello').toBeTypeofString();
-  smartexpect.expect(1).not.toBeTypeofString();
-  smartexpect.expect(true).toBeTypeofBoolean();
-  smartexpect.expect(true).not.toBeTypeofNumber();
-});
-
-tap.test('async tests', async (toolsArg) => {
-  const deferred = toolsArg.defer();
-  toolsArg.delayFor(4000).then(() => {
-    deferred.resolve('hello');
-  });
-  await smartexpect.expectAsync(deferred.promise).timeout(5000).toBeTypeofString();
-  await smartexpect.expectAsync(deferred.promise).not.toBeTypeofBoolean();
-});
-
-tap.test('should check equality', async () => {
-  smartexpect.expect('hithere').toEqual('hithere');
-  smartexpect.expect('hithere').not.toEqual('hithere2');
-});
-
-tap.test('should check for regexp matching', async () => {
-  smartexpect.expect('hithere').toMatch(/hi/);
-  smartexpect.expect('hithere').not.toMatch(/ho/);
-});
-
-tap.test('should correctly state property presence', async () => {
-  const testObject = {
-    aprop: 'hello',
-  };
-
-  smartexpect.expect(testObject).toHaveProperty('aprop');
-  smartexpect.expect(testObject).not.toHaveProperty('aprop2');
-});
-
-tap.test('should be greater than', async () => {
-  smartexpect.expect(4).toBeGreaterThan(3);
-  smartexpect.expect(4).toBeLessThan(5);
-});
-
-tap.test('should correctly determine toContain', async () => {
-  const hello = {
-    socool: 'yes',
-  };
-  const testArray = [hello];
-  smartexpect.expect(testArray).toContain(hello);
-});
-
-tap.start();

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartexpect',
-  version: '1.1.0',
+  version: '1.6.1',
   description: 'A testing library to manage expectations in code, offering both synchronous and asynchronous assertion methods.'
 }

ts/index.ts

@@ -1,5 +1,3 @@
-import * as plugins from './smartexpect.plugins.js';
-
 import { Assertion } from './smartexpect.classes.assertion.js';
 
 export const expect = (baseArg: any) => {
@@ -11,3 +9,4 @@ export const expectAsync = (baseArg: any) => {
   const assertion = new Assertion(baseArg, 'async');
   return assertion;
 };
+

ts/smartexpect.classes.assertion.ts

@@ -5,9 +5,13 @@ export type TExecutionType = 'sync' | 'async';
 export class Assertion {
   executionMode: TExecutionType;
   baseReference: any;
-  propertyDrillDown: string[] = [];
+  propertyDrillDown: Array<string | number> = [];
+
   private notSetting = false;
   private timeoutSetting = 0;
+  private failMessage: string;
+  private successMessage: string;
+
   constructor(baseReferenceArg: any, executionModeArg: TExecutionType) {
     this.baseReference = baseReferenceArg;
     this.executionMode = executionModeArg;
@@ -16,11 +20,70 @@ export class Assertion {
   private getObjectToTestReference() {
     let returnObjectToTestReference = this.baseReference;
     for (const property of this.propertyDrillDown) {
+      if (returnObjectToTestReference == null) {
+        // if it's null or undefined, stop
+        break;
+      }
+
+      // We just directly access with bracket notation.
+      // If property is a string, it's like obj["someProp"];
+      // If property is a number, it's like obj[0].
       returnObjectToTestReference = returnObjectToTestReference[property];
     }
     return returnObjectToTestReference;
   }
 
+  private formatDrillDown(): string {
+    if (!this.propertyDrillDown || this.propertyDrillDown.length === 0) {
+      return '';
+    }
+    
+    const path = this.propertyDrillDown.map(prop => {
+      if (typeof prop === 'number') {
+        return `[${prop}]`;
+      } else {
+        return `.${prop}`;
+      }
+    }).join('');
+    
+    return path;
+  }
+  
+  private formatValue(value: any): string {
+    if (value === null) {
+      return 'null';
+    } else if (value === undefined) {
+      return 'undefined';
+    } else if (typeof value === 'object') {
+      try {
+        return JSON.stringify(value);
+      } catch (e) {
+        return `[Object ${value.constructor.name}]`;
+      }
+    } else if (typeof value === 'function') {
+      return `[Function${value.name ? ': ' + value.name : ''}]`;
+    } else if (typeof value === 'string') {
+      return `"${value}"`;
+    } else {
+      return String(value);
+    }
+  }
+
+  private createErrorMessage(message: string): string {
+    if (this.failMessage) {
+      return this.failMessage;
+    }
+    
+    const testValue = this.getObjectToTestReference();
+    const formattedValue = this.formatValue(testValue);
+    const drillDown = this.formatDrillDown();
+    
+    // Replace placeholders in the message
+    return message
+      .replace('{value}', formattedValue)
+      .replace('{path}', drillDown || '');
+  }
+
   public get not() {
     this.notSetting = true;
     return this;
@@ -31,6 +94,16 @@ export class Assertion {
     return this;
   }
 
+  public setFailMessage(failMessageArg: string) {
+    this.failMessage = failMessageArg;
+    return this;
+  }
+
+  public setSuccessMessage(successMessageArg: string) {
+    this.successMessage = successMessageArg;
+    return this;
+  }
+
   private runCheck(checkFunction: () => any) {
     const runDirectOrNegated = (checkFunction: () => any) => {
       if (!this.notSetting) {
@@ -43,7 +116,7 @@ export class Assertion {
           isOk = true;
         }
         if (!isOk) {
-          throw new Error('Negated assertion is not ok!');
+          throw new Error(this.failMessage || 'Negated assertion failed');
         }
       }
     };
@@ -51,16 +124,16 @@ export class Assertion {
     if (this.executionMode === 'async') {
       const done = plugins.smartpromise.defer();
       if (!(this.baseReference instanceof Promise)) {
-        done.reject(new Error(`${this.baseReference} is not of type promise.`));
+        done.reject(new Error(`Expected a Promise but received: ${this.formatValue(this.baseReference)}`));
       } else {
         if (this.timeoutSetting) {
           plugins.smartdelay.delayFor(this.timeoutSetting).then(() => {
             if (done.status === 'pending') {
-              done.reject(new Error(`${this.baseReference} timed out at ${this.timeoutSetting}!`));
+              done.reject(new Error(`Promise timed out after ${this.timeoutSetting}ms`));
             }
           });
         }
-        this.baseReference.then((promiseResultArg) => {
+        this.baseReference.then((promiseResultArg: any) => {
           this.baseReference = promiseResultArg;
           done.resolve(runDirectOrNegated(checkFunction));
         });
@@ -71,29 +144,22 @@ export class Assertion {
     }
   }
 
-  /**
-   * checks if the given object is defined
-   */
   public toBeDefined() {
     return this.runCheck(() => {
       if (this.getObjectToTestReference() === undefined) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not defined`
+          this.createErrorMessage('Expected value{path} to be defined, but got undefined')
         );
       }
     });
   }
 
-  /**
-   * checks if the given object is not defined
-   */
   public toBeTypeofString() {
     return this.runCheck(() => {
-      if (typeof this.getObjectToTestReference() !== 'string') {
+      const value = this.getObjectToTestReference();
+      if (typeof value !== 'string') {
         throw new Error(
-          `Assertion failed: ${this.baseReference} with drill down ${
-            this.propertyDrillDown
-          } is not of type string, but typeof ${typeof this.baseReference}`
+          this.createErrorMessage(`Expected value{path} to be of type string, but got ${typeof value}`)
         );
       }
     });
@@ -101,11 +167,10 @@ export class Assertion {
 
   public toBeTypeofNumber() {
     return this.runCheck(() => {
-      if (typeof this.getObjectToTestReference() !== 'number') {
+      const value = this.getObjectToTestReference();
+      if (typeof value !== 'number') {
         throw new Error(
-          `Assertion failed: ${this.baseReference} with drill down ${
-            this.propertyDrillDown
-          } is not of type string, but typeof ${typeof this.baseReference}`
+          this.createErrorMessage(`Expected value{path} to be of type number, but got ${typeof value}`)
         );
       }
     });
@@ -113,11 +178,22 @@ export class Assertion {
 
   public toBeTypeofBoolean() {
     return this.runCheck(() => {
-      if (typeof this.getObjectToTestReference() !== 'boolean') {
+      const value = this.getObjectToTestReference();
+      if (typeof value !== 'boolean') {
         throw new Error(
-          `Assertion failed: ${this.baseReference} with drill down ${
-            this.propertyDrillDown
-          } is not of type string, but typeof ${typeof this.baseReference}`
+          this.createErrorMessage(`Expected value{path} to be of type boolean, but got ${typeof value}`)
+        );
+      }
+    });
+  }
+
+  public toBeTypeOf(expectedType: string) {
+    return this.runCheck(() => {
+      const value = this.getObjectToTestReference();
+      const actualType = typeof value;
+      if (actualType !== expectedType) {
+        throw new Error(
+          this.createErrorMessage(`Expected value{path} to be of type ${expectedType}, but got ${actualType}`)
         );
       }
     });
@@ -125,10 +201,11 @@ export class Assertion {
 
   public toEqual(comparisonObject: any) {
     return this.runCheck(() => {
-      const result = plugins.fastDeepEqual(this.getObjectToTestReference(), comparisonObject);
+      const value = this.getObjectToTestReference();
+      const result = plugins.fastDeepEqual(value, comparisonObject);
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not equal ${comparisonObject}`
+          this.createErrorMessage(`Expected value{path} to equal ${this.formatValue(comparisonObject)}`)
         );
       }
     });
@@ -136,10 +213,11 @@ export class Assertion {
 
   public toMatch(comparisonObject: RegExp) {
     return this.runCheck(() => {
-      const result = comparisonObject.test(this.getObjectToTestReference());
+      const value = this.getObjectToTestReference();
+      const result = comparisonObject.test(value);
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not equal ${comparisonObject}`
+          this.createErrorMessage(`Expected value{path} to match regex ${comparisonObject}`)
         );
       }
     });
@@ -147,12 +225,11 @@ export class Assertion {
 
   public toBeTrue() {
     return this.runCheck(() => {
-      const result =
-        typeof this.getObjectToTestReference() === 'boolean' &&
-        this.getObjectToTestReference() === true;
+      const value = this.getObjectToTestReference();
+      const result = typeof value === 'boolean' && value === true;
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not true or not of type boolean`
+          this.createErrorMessage(`Expected value{path} to be true, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -160,12 +237,11 @@ export class Assertion {
 
   public toBeFalse() {
     return this.runCheck(() => {
-      const result =
-        typeof this.getObjectToTestReference() === 'boolean' &&
-        this.getObjectToTestReference() === false;
+      const value = this.getObjectToTestReference();
+      const result = typeof value === 'boolean' && value === false;
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not false or not of type boolean`
+          this.createErrorMessage(`Expected value{path} to be false, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -173,10 +249,11 @@ export class Assertion {
 
   public toBeInstanceOf(classArg: any) {
     return this.runCheck(() => {
-      const result = this.getObjectToTestReference() instanceof classArg;
+      const value = this.getObjectToTestReference();
+      const result = value instanceof classArg;
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not an instance of ${classArg}`
+          this.createErrorMessage(`Expected value{path} to be an instance of ${classArg.name || 'provided class'}`)
         );
       }
     });
@@ -184,16 +261,18 @@ export class Assertion {
 
   public toHaveProperty(propertyArg: string, equalsArg?: any) {
     return this.runCheck(() => {
-      const result = !!this.getObjectToTestReference()[propertyArg];
-      if (!result) {
+      const obj = this.getObjectToTestReference();
+      if (!obj || !(propertyArg in obj)) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not have property ${propertyArg}`
+          this.createErrorMessage(`Expected value{path} to have property '${propertyArg}'`)
         );
       }
-      if (equalsArg) {
-        if (result !== equalsArg) {
+      if (equalsArg !== undefined) {
+        if (obj[propertyArg] !== equalsArg) {
           throw new Error(
-            `${this.baseReference} with drill down ${this.propertyDrillDown} does have property ${propertyArg}, but it does not equal ${equalsArg}`
+            this.createErrorMessage(
+              `Expected property '${propertyArg}' of value{path} to equal ${this.formatValue(equalsArg)}, but got ${this.formatValue(obj[propertyArg])}`
+            )
           );
         }
       }
@@ -213,7 +292,9 @@ export class Assertion {
         }
 
         if (!obj || !(property in obj)) {
-          throw new Error(`Missing property at path "${currentPath}" in ${this.baseReference}`);
+          throw new Error(
+            this.createErrorMessage(`Expected value{path} to have property at path '${currentPath}'`)
+          );
         }
         obj = obj[property];
       }
@@ -222,10 +303,11 @@ export class Assertion {
 
   public toBeGreaterThan(numberArg: number) {
     return this.runCheck(() => {
-      const result = this.getObjectToTestReference() > numberArg;
+      const value = this.getObjectToTestReference();
+      const result = value > numberArg;
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not greater than ${numberArg}`
+          this.createErrorMessage(`Expected value{path} to be greater than ${numberArg}, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -233,10 +315,11 @@ export class Assertion {
 
   public toBeLessThan(numberArg: number) {
     return this.runCheck(() => {
-      const result = this.getObjectToTestReference() < numberArg;
+      const value = this.getObjectToTestReference();
+      const result = value < numberArg;
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not less than ${numberArg}`
+          this.createErrorMessage(`Expected value{path} to be less than ${numberArg}, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -244,10 +327,11 @@ export class Assertion {
 
   public toBeNull() {
     return this.runCheck(() => {
-      const result = this.getObjectToTestReference() === null;
+      const value = this.getObjectToTestReference();
+      const result = value === null;
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not null`
+          this.createErrorMessage(`Expected value{path} to be null, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -255,10 +339,11 @@ export class Assertion {
 
   public toBeUndefined() {
     return this.runCheck(() => {
-      const result = this.getObjectToTestReference() === undefined;
+      const value = this.getObjectToTestReference();
+      const result = value === undefined;
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not undefined`
+          this.createErrorMessage(`Expected value{path} to be undefined, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -266,26 +351,25 @@ export class Assertion {
 
   public toBeNullOrUndefined() {
     return this.runCheck(() => {
-      const result =
-        this.getObjectToTestReference() === null || this.getObjectToTestReference() === undefined;
+      const value = this.getObjectToTestReference();
+      const result = value === null || value === undefined;
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not null or undefined`
+          this.createErrorMessage(`Expected value{path} to be null or undefined, but got ${this.formatValue(value)}`)
         );
       }
     });
   }
 
-  // Array
+  // Array checks
 
   public toContain(itemArg: any) {
     return this.runCheck(() => {
-      const result =
-        this.getObjectToTestReference() instanceof Array &&
-        this.getObjectToTestReference().includes(itemArg);
+      const value = this.getObjectToTestReference();
+      const result = Array.isArray(value) && value.includes(itemArg);
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not contain ${itemArg}`
+          this.createErrorMessage(`Expected array{path} to contain ${this.formatValue(itemArg)}`)
         );
       }
     });
@@ -293,40 +377,49 @@ export class Assertion {
 
   public toBeEmptyArray() {
     return this.runCheck(() => {
-      const arrayRef = this.getObjectToTestReference();
-      if (!Array.isArray(arrayRef) || arrayRef.length !== 0) {
-        throw new Error(`Expected ${this.baseReference} to be an empty array, but it was not.`);
+      const value = this.getObjectToTestReference();
+      if (!Array.isArray(value)) {
+        throw new Error(
+          this.createErrorMessage(`Expected value{path} to be an array, but got ${typeof value}`)
+        );
+      }
+      if (value.length !== 0) {
+        throw new Error(
+          this.createErrorMessage(`Expected array{path} to be empty, but it has ${value.length} elements`)
+        );
       }
     });
   }
 
   public toContainAll(values: any[]) {
     return this.runCheck(() => {
-      const arrayRef = this.getObjectToTestReference();
-      if (!Array.isArray(arrayRef)) {
-        throw new Error(`Expected ${this.baseReference} to be an array.`);
+      const arr = this.getObjectToTestReference();
+      if (!Array.isArray(arr)) {
+        throw new Error(
+          this.createErrorMessage(`Expected value{path} to be an array, but got ${typeof arr}`)
+        );
       }
-
-      for (const value of values) {
-        if (!arrayRef.includes(value)) {
-          throw new Error(
-            `Expected ${this.baseReference} to include value "${value}", but it did not.`
-          );
-        }
+      
+      const missing = values.filter(v => !arr.includes(v));
+      if (missing.length > 0) {
+        throw new Error(
+          this.createErrorMessage(`Expected array{path} to contain all values ${this.formatValue(values)}, but missing: ${this.formatValue(missing)}`)
+        );
       }
     });
   }
 
   public toExclude(value: any) {
     return this.runCheck(() => {
-      const arrayRef = this.getObjectToTestReference();
-      if (!Array.isArray(arrayRef)) {
-        throw new Error(`Expected ${this.baseReference} to be an array.`);
-      }
-
-      if (arrayRef.includes(value)) {
+      const arr = this.getObjectToTestReference();
+      if (!Array.isArray(arr)) {
         throw new Error(
-          `Expected ${this.baseReference} to exclude value "${value}", but it included it.`
+          this.createErrorMessage(`Expected value{path} to be an array, but got ${typeof arr}`)
+        );
+      }
+      if (arr.includes(value)) {
+        throw new Error(
+          this.createErrorMessage(`Expected array{path} to exclude ${this.formatValue(value)}, but it was found`)
         );
       }
     });
@@ -334,11 +427,11 @@ export class Assertion {
 
   public toStartWith(itemArg: any) {
     return this.runCheck(() => {
-      const testObject = this.getObjectToTestReference();
-      const result = typeof testObject === 'string' && testObject.startsWith(itemArg);
+      const value = this.getObjectToTestReference();
+      const result = typeof value === 'string' && value.startsWith(itemArg);
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not contain ${itemArg}`
+          this.createErrorMessage(`Expected string{path} to start with "${itemArg}", but got "${value}"`)
         );
       }
     });
@@ -346,24 +439,23 @@ export class Assertion {
 
   public toEndWith(itemArg: any) {
     return this.runCheck(() => {
-      const testObject = this.getObjectToTestReference();
-      const result = typeof testObject === 'string' && testObject.endsWith(itemArg);
+      const value = this.getObjectToTestReference();
+      const result = typeof value === 'string' && value.endsWith(itemArg);
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not contain ${itemArg}`
+          this.createErrorMessage(`Expected string{path} to end with "${itemArg}", but got "${value}"`)
         );
       }
     });
   }
 
-  // ... previous code ...
-
   public toBeOneOf(values: any[]) {
     return this.runCheck(() => {
-      const result = values.includes(this.getObjectToTestReference());
+      const value = this.getObjectToTestReference();
+      const result = values.includes(value);
       if (!result) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not one of ${values}`
+          this.createErrorMessage(`Expected value{path} to be one of ${this.formatValue(values)}, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -372,9 +464,14 @@ export class Assertion {
   public toHaveLength(length: number) {
     return this.runCheck(() => {
       const obj = this.getObjectToTestReference();
-      if (typeof obj.length !== 'number' || obj.length !== length) {
+      if (typeof obj.length !== 'number') {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not have a length of ${length}`
+          this.createErrorMessage(`Expected value{path} to have a length property, but it doesn't`)
+        );
+      }
+      if (obj.length !== length) {
+        throw new Error(
+          this.createErrorMessage(`Expected value{path} to have length ${length}, but got length ${obj.length}`)
         );
       }
     });
@@ -382,10 +479,12 @@ export class Assertion {
 
   public toBeCloseTo(value: number, precision = 2) {
     return this.runCheck(() => {
-      const difference = Math.abs(this.getObjectToTestReference() - value);
-      if (difference > Math.pow(10, -precision) / 2) {
+      const actual = this.getObjectToTestReference();
+      const difference = Math.abs(actual - value);
+      const epsilon = Math.pow(10, -precision) / 2;
+      if (difference > epsilon) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not close to ${value} up to ${precision} decimal places`
+          this.createErrorMessage(`Expected value{path} to be close to ${value} (within ${epsilon}), but the difference was ${difference}`)
         );
       }
     });
@@ -393,28 +492,42 @@ export class Assertion {
 
   public toThrow(expectedError?: any) {
     return this.runCheck(() => {
+      const fn = this.getObjectToTestReference();
+      if (typeof fn !== 'function') {
+        throw new Error(
+          this.createErrorMessage(`Expected value{path} to be a function, but got ${typeof fn}`)
+        );
+      }
+      
       let thrown = false;
+      let error: any;
+      
       try {
-        this.getObjectToTestReference()();
+        fn();
       } catch (e) {
         thrown = true;
+        error = e;
         if (expectedError && !(e instanceof expectedError)) {
           throw new Error(
-            `Expected function to throw ${expectedError.name}, but it threw ${e.name}`
+            this.createErrorMessage(`Expected function{path} to throw ${expectedError.name}, but it threw ${e.constructor.name}`)
           );
         }
       }
+      
       if (!thrown) {
-        throw new Error(`Expected function to throw, but it didn't.`);
+        throw new Error(
+          this.createErrorMessage(`Expected function{path} to throw, but it didn't throw any error`)
+        );
       }
     });
   }
 
   public toBeTruthy() {
     return this.runCheck(() => {
-      if (!this.getObjectToTestReference()) {
+      const value = this.getObjectToTestReference();
+      if (!value) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not truthy`
+          this.createErrorMessage(`Expected value{path} to be truthy, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -422,9 +535,10 @@ export class Assertion {
 
   public toBeFalsy() {
     return this.runCheck(() => {
-      if (this.getObjectToTestReference()) {
+      const value = this.getObjectToTestReference();
+      if (value) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not falsy`
+          this.createErrorMessage(`Expected value{path} to be falsy, but got ${this.formatValue(value)}`)
         );
       }
     });
@@ -432,9 +546,10 @@ export class Assertion {
 
   public toBeGreaterThanOrEqual(numberArg: number) {
     return this.runCheck(() => {
-      if (this.getObjectToTestReference() <= numberArg) {
+      const value = this.getObjectToTestReference();
+      if (value < numberArg) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not greater than or equal to ${numberArg}`
+          this.createErrorMessage(`Expected value{path} to be greater than or equal to ${numberArg}, but got ${value}`)
         );
       }
     });
@@ -442,9 +557,10 @@ export class Assertion {
 
   public toBeLessThanOrEqual(numberArg: number) {
     return this.runCheck(() => {
-      if (this.getObjectToTestReference() >= numberArg) {
+      const value = this.getObjectToTestReference();
+      if (value > numberArg) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not less than or equal to ${numberArg}`
+          this.createErrorMessage(`Expected value{path} to be less than or equal to ${numberArg}, but got ${value}`)
         );
       }
     });
@@ -452,10 +568,11 @@ export class Assertion {
 
   public toMatchObject(objectArg: object) {
     return this.runCheck(() => {
-      const partialMatch = plugins.fastDeepEqual(this.getObjectToTestReference(), objectArg); // Note: Implement a deep comparison function or use one from a library
-      if (!partialMatch) {
+      const value = this.getObjectToTestReference();
+      const matchResult = plugins.fastDeepEqual(value, objectArg);
+      if (!matchResult) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not match the object ${objectArg}`
+          this.createErrorMessage(`Expected value{path} to match ${this.formatValue(objectArg)}`)
         );
       }
     });
@@ -464,10 +581,16 @@ export class Assertion {
   public toContainEqual(value: any) {
     return this.runCheck(() => {
       const arr = this.getObjectToTestReference();
-      const found = arr.some((item: any) => plugins.fastDeepEqual(item, value)); // Assuming fastDeepEqual checks deep equality
+      if (!Array.isArray(arr)) {
+        throw new Error(
+          this.createErrorMessage(`Expected value{path} to be an array, but got ${typeof arr}`)
+        );
+      }
+      
+      const found = arr.some((item: any) => plugins.fastDeepEqual(item, value));
       if (!found) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not contain the value ${value}`
+          this.createErrorMessage(`Expected array{path} to contain an item equal to ${this.formatValue(value)}`)
         );
       }
     });
@@ -475,9 +598,10 @@ export class Assertion {
 
   public toBeArray() {
     return this.runCheck(() => {
-      if (!Array.isArray(this.getObjectToTestReference())) {
+      const value = this.getObjectToTestReference();
+      if (!Array.isArray(value)) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not an array`
+          this.createErrorMessage(`Expected value{path} to be an array, but got ${typeof value}`)
         );
       }
     });
@@ -485,9 +609,15 @@ export class Assertion {
 
   public toInclude(substring: string) {
     return this.runCheck(() => {
-      if (!this.getObjectToTestReference().includes(substring)) {
+      const value = this.getObjectToTestReference();
+      if (typeof value !== 'string') {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not include the substring ${substring}`
+          this.createErrorMessage(`Expected value{path} to be a string, but got ${typeof value}`)
+        );
+      }
+      if (!value.includes(substring)) {
+        throw new Error(
+          this.createErrorMessage(`Expected string{path} to include "${substring}", but it doesn't`)
         );
       }
     });
@@ -496,9 +626,14 @@ export class Assertion {
   public toHaveLengthGreaterThan(length: number) {
     return this.runCheck(() => {
       const obj = this.getObjectToTestReference();
-      if (typeof obj.length !== 'number' || obj.length <= length) {
+      if (typeof obj.length !== 'number') {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not have a length greater than ${length}`
+          this.createErrorMessage(`Expected value{path} to have a length property, but it doesn't`)
+        );
+      }
+      if (obj.length <= length) {
+        throw new Error(
+          this.createErrorMessage(`Expected value{path} to have length greater than ${length}, but got length ${obj.length}`)
         );
       }
     });
@@ -507,9 +642,14 @@ export class Assertion {
   public toHaveLengthLessThan(length: number) {
     return this.runCheck(() => {
       const obj = this.getObjectToTestReference();
-      if (typeof obj.length !== 'number' || obj.length >= length) {
+      if (typeof obj.length !== 'number') {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} does not have a length less than ${length}`
+          this.createErrorMessage(`Expected value{path} to have a length property, but it doesn't`)
+        );
+      }
+      if (obj.length >= length) {
+        throw new Error(
+          this.createErrorMessage(`Expected value{path} to have length less than ${length}, but got length ${obj.length}`)
         );
       }
     });
@@ -517,9 +657,10 @@ export class Assertion {
 
   public toBeDate() {
     return this.runCheck(() => {
-      if (!(this.getObjectToTestReference() instanceof Date)) {
+      const value = this.getObjectToTestReference();
+      if (!(value instanceof Date)) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not a date`
+          this.createErrorMessage(`Expected value{path} to be a Date, but got ${value.constructor ? value.constructor.name : typeof value}`)
         );
       }
     });
@@ -527,9 +668,15 @@ export class Assertion {
 
   public toBeBeforeDate(date: Date) {
     return this.runCheck(() => {
-      if (!(this.getObjectToTestReference() < date)) {
+      const value = this.getObjectToTestReference();
+      if (!(value instanceof Date)) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not before ${date}`
+          this.createErrorMessage(`Expected value{path} to be a Date, but got ${value.constructor ? value.constructor.name : typeof value}`)
+        );
+      }
+      if (value >= date) {
+        throw new Error(
+          this.createErrorMessage(`Expected date{path} to be before ${date.toISOString()}, but got ${value.toISOString()}`)
         );
       }
     });
@@ -537,24 +684,53 @@ export class Assertion {
 
   public toBeAfterDate(date: Date) {
     return this.runCheck(() => {
-      if (!(this.getObjectToTestReference() > date)) {
+      const value = this.getObjectToTestReference();
+      if (!(value instanceof Date)) {
         throw new Error(
-          `${this.baseReference} with drill down ${this.propertyDrillDown} is not after ${date}`
+          this.createErrorMessage(`Expected value{path} to be a Date, but got ${value.constructor ? value.constructor.name : typeof value}`)
+        );
+      }
+      if (value <= date) {
+        throw new Error(
+          this.createErrorMessage(`Expected date{path} to be after ${date.toISOString()}, but got ${value.toISOString()}`)
         );
       }
     });
   }
 
-  public customAssertion(assertionFunction: (value: any) => boolean, errorMessage: string) {
+  public customAssertion(
+    assertionFunction: (value: any) => boolean,
+    errorMessage: string
+  ) {
     return this.runCheck(() => {
-      if (!assertionFunction(this.getObjectToTestReference())) {
-        throw new Error(errorMessage);
+      const value = this.getObjectToTestReference();
+      if (!assertionFunction(value)) {
+        throw new Error(this.failMessage || errorMessage);
       }
     });
   }
 
+  /**
+   * Drill into a property
+   */
   public property(propertyNameArg: string) {
     this.propertyDrillDown.push(propertyNameArg);
     return this;
   }
-}
+
+  /**
+   * Drill into an array index
+   */
+  public arrayItem(indexArg: number) {
+    // Save the number (instead of "[index]")
+    this.propertyDrillDown.push(indexArg);
+    return this;
+  }
+
+  public log() {
+    console.log(`Current value:`);
+    console.log(JSON.stringify(this.getObjectToTestReference(), null, 2));
+    console.log(`Path: ${this.formatDrillDown() || '(root)'}`);
+    return this;
+  }
+}

tsconfig.json

@@ -1,6 +1,7 @@
 {
   "compilerOptions": {
     "experimentalDecorators": true,
+    "emitDecoratorMetadata": true,
     "useDefineForClassFields": false,
     "target": "ES2022",
     "module": "NodeNext",