fix(logging): handle mid-line streaming output in test logger and add streaming tests

changelog.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## 2026-01-19 - 3.1.6 - fix(logging)
+handle mid-line streaming output in test logger and add streaming tests
+
+- Introduce isOutputMidLine flag to track when streaming output does not end with a newline
+- Only prepend the visual prefix at the start of a line and append segments to the last buffered entry when mid-line
+- Write consistent output to log files for both complete lines and raw streaming segments
+- Add tests to exercise streaming behavior: test/tstest/test.gap-debug.ts and test/tstest/test.gap-debug2.ts
+
 ## 2026-01-19 - 3.1.5 - fix(tstest)
 preserve streaming console output and correctly buffer incomplete TAP lines
 

test/tstest/test.gap-debug.ts

@@ -0,0 +1,12 @@
+import { tap, expect } from '../../ts_tapbundle/index.js';
+
+tap.test('check for gaps in streaming', async () => {
+  // This should print "ABCD" with no gaps
+  process.stdout.write("A");
+  process.stdout.write("B");
+  process.stdout.write("C");
+  process.stdout.write("D\n");
+  expect(true).toEqual(true);
+});
+
+export default tap.start();

test/tstest/test.gap-debug2.ts

@@ -0,0 +1,14 @@
+import { tap, expect } from '../../ts_tapbundle/index.js';
+
+tap.test('streaming with delays', async (tools) => {
+  // Simulate real streaming with delays
+  process.stdout.write("Progress: [");
+  for (let i = 0; i < 10; i++) {
+    await tools.delayFor(50);
+    process.stdout.write("=");
+  }
+  process.stdout.write("]\n");
+  expect(true).toEqual(true);
+});
+
+export default tap.start();

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@git.zone/tstest',
-  version: '3.1.5',
+  version: '3.1.6',
   description: 'a test utility to run tests that match test/**/*.ts'
 }

ts/tstest.logging.ts

@@ -44,6 +44,7 @@ export class TsTestLogger {
   private currentTestLogFile: string | null = null;
   private currentTestLogs: string[] = []; // Buffer for current test logs
   private currentTestFailed: boolean = false;
+  private isOutputMidLine: boolean = false; // Track whether we're mid-line for streaming output
   
   constructor(options: LogOptions = {}) {
     this.options = options;
@@ -189,6 +190,7 @@ export class TsTestLogger {
     // Reset test-specific state
     this.currentTestLogs = [];
     this.currentTestFailed = false;
+    this.isOutputMidLine = false;
     
     // Only set up test log file if --logfile option is specified
     if (this.options.logFile) {
@@ -352,17 +354,28 @@ export class TsTestLogger {
   testConsoleOutput(message: string) {
     if (this.options.json) return;
 
+    const prefix = '   ';
     // In verbose mode, show console output immediately
     if (this.options.verbose) {
-      this.log(this.format(`   ${message}`, 'dim'));
+      // Only add prefix if we're starting a new line
+      const output = this.isOutputMidLine ? message : prefix + message;
+      this.log(this.format(output, 'dim'));
     } else {
       // In non-verbose mode, buffer the logs
+      if (this.isOutputMidLine && this.currentTestLogs.length > 0) {
+        // Append to the last buffered entry since we're mid-line
+        this.currentTestLogs[this.currentTestLogs.length - 1] += message;
+      } else {
         this.currentTestLogs.push(message);
       }
+    }
+
+    // Reset mid-line state since we just output a complete line
+    this.isOutputMidLine = false;
 
     // Always log to test file if --logfile is specified
     if (this.currentTestLogFile) {
-      this.logToTestFile(`   ${message}`);
+      this.logToTestFile(`${prefix}${message}`);
     }
   }
 
@@ -371,13 +384,15 @@ export class TsTestLogger {
     if (this.options.json) return;
 
     const prefix = '   ';
+    // Only add prefix if we're starting a new line (not mid-line)
+    const output = this.isOutputMidLine ? message : prefix + message;
+
     if (this.options.verbose) {
       // Use process.stdout.write to preserve streaming without adding newlines
-      process.stdout.write(this.format(prefix + message, 'dim'));
+      process.stdout.write(this.format(output, 'dim'));
     } else {
-      // Buffer without trailing newline - append to last entry if exists and incomplete
+      // Buffer mode: append to last entry if mid-line
-      if (this.currentTestLogs.length > 0) {
+      if (this.isOutputMidLine && this.currentTestLogs.length > 0) {
-        // Append to the last buffered entry (for streaming segments)
         this.currentTestLogs[this.currentTestLogs.length - 1] += message;
       } else {
         this.currentTestLogs.push(message);
@@ -386,8 +401,11 @@ export class TsTestLogger {
 
     // Log to test file without adding newline
     if (this.currentTestLogFile) {
-      this.logToTestFileRaw(prefix + message);
+      this.logToTestFileRaw(output);
     }
+
+    // We're now mid-line (no newline was written)
+    this.isOutputMidLine = true;
   }
 
   private logToTestFileRaw(message: string) {