feat: migrate testing framework to Bun and update test configurations

- Updated GitHub Actions workflow to use Bun's test runner and coverage reporting.
- Added comprehensive testing documentation for the Gitea Mirror project.
- Refactored test scripts in package.json to align with Bun's testing commands.
- Created new test files for database, Gitea, GitHub, health, and mirroring APIs.
- Implemented mock functions for API tests to handle various scenarios and responses.
- Established a test setup file for consistent test environment configuration.

src/lib/utils/concurrency.test.ts

@@ -0,0 +1,167 @@
+import { describe, test, expect, mock } from "bun:test";
+import { processInParallel, processWithRetry } from "./concurrency";
+
+describe("processInParallel", () => {
+  test("processes items in parallel with concurrency control", async () => {
+    // Create an array of numbers to process
+    const items = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+    
+    // Create a mock function to track execution
+    const processItem = mock(async (item: number) => {
+      // Simulate async work
+      await new Promise(resolve => setTimeout(resolve, 10));
+      return item * 2;
+    });
+    
+    // Create a mock progress callback
+    const onProgress = mock((completed: number, total: number, result?: number) => {
+      // Progress tracking
+    });
+    
+    // Process the items with a concurrency limit of 3
+    const results = await processInParallel(
+      items,
+      processItem,
+      3,
+      onProgress
+    );
+    
+    // Verify results
+    expect(results).toEqual([2, 4, 6, 8, 10, 12, 14, 16, 18, 20]);
+    
+    // Verify that processItem was called for each item
+    expect(processItem).toHaveBeenCalledTimes(10);
+    
+    // Verify that onProgress was called for each item
+    expect(onProgress).toHaveBeenCalledTimes(10);
+    
+    // Verify the last call to onProgress had the correct completed/total values
+    expect(onProgress.mock.calls[9][0]).toBe(10); // completed
+    expect(onProgress.mock.calls[9][1]).toBe(10); // total
+  });
+  
+  test("handles errors in processing", async () => {
+    // Create an array of numbers to process
+    const items = [1, 2, 3, 4, 5];
+    
+    // Create a mock function that throws an error for item 3
+    const processItem = mock(async (item: number) => {
+      if (item === 3) {
+        throw new Error("Test error");
+      }
+      return item * 2;
+    });
+    
+    // Create a spy for console.error
+    const originalConsoleError = console.error;
+    const consoleErrorMock = mock(() => {});
+    console.error = consoleErrorMock;
+    
+    try {
+      // Process the items
+      const results = await processInParallel(items, processItem);
+      
+      // Verify results (should have 4 items, missing the one that errored)
+      expect(results).toEqual([2, 4, 8, 10]);
+      
+      // Verify that processItem was called for each item
+      expect(processItem).toHaveBeenCalledTimes(5);
+      
+      // Verify that console.error was called once
+      expect(consoleErrorMock).toHaveBeenCalledTimes(1);
+    } finally {
+      // Restore console.error
+      console.error = originalConsoleError;
+    }
+  });
+});
+
+describe("processWithRetry", () => {
+  test("retries failed operations", async () => {
+    // Create an array of numbers to process
+    const items = [1, 2, 3];
+    
+    // Create a counter to track retry attempts
+    const attemptCounts: Record<number, number> = { 1: 0, 2: 0, 3: 0 };
+    
+    // Create a mock function that fails on first attempt for item 2
+    const processItem = mock(async (item: number) => {
+      attemptCounts[item]++;
+      
+      if (item === 2 && attemptCounts[item] === 1) {
+        throw new Error("Temporary error");
+      }
+      
+      return item * 2;
+    });
+    
+    // Create a mock for the onRetry callback
+    const onRetry = mock((item: number, error: Error, attempt: number) => {
+      // Retry tracking
+    });
+    
+    // Process the items with retry
+    const results = await processWithRetry(items, processItem, {
+      maxRetries: 2,
+      retryDelay: 10,
+      onRetry,
+    });
+    
+    // Verify results
+    expect(results).toEqual([2, 4, 6]);
+    
+    // Verify that item 2 was retried once
+    expect(attemptCounts[1]).toBe(1); // No retries
+    expect(attemptCounts[2]).toBe(2); // One retry
+    expect(attemptCounts[3]).toBe(1); // No retries
+    
+    // Verify that onRetry was called once
+    expect(onRetry).toHaveBeenCalledTimes(1);
+    expect(onRetry.mock.calls[0][0]).toBe(2); // item
+    expect(onRetry.mock.calls[0][2]).toBe(1); // attempt
+  });
+  
+  test("gives up after max retries", async () => {
+    // Create an array of numbers to process
+    const items = [1, 2];
+    
+    // Create a mock function that always fails for item 2
+    const processItem = mock(async (item: number) => {
+      if (item === 2) {
+        throw new Error("Persistent error");
+      }
+      return item * 2;
+    });
+    
+    // Create a mock for the onRetry callback
+    const onRetry = mock((item: number, error: Error, attempt: number) => {
+      // Retry tracking
+    });
+    
+    // Create a spy for console.error
+    const originalConsoleError = console.error;
+    const consoleErrorMock = mock(() => {});
+    console.error = consoleErrorMock;
+    
+    try {
+      // Process the items with retry
+      const results = await processWithRetry(items, processItem, {
+        maxRetries: 2,
+        retryDelay: 10,
+        onRetry,
+      });
+      
+      // Verify results (should have 1 item, missing the one that errored)
+      expect(results).toEqual([2]);
+      
+      // Verify that onRetry was called twice (for 2 retry attempts)
+      expect(onRetry).toHaveBeenCalledTimes(2);
+      
+      // Verify that console.error was called once
+      expect(consoleErrorMock).toHaveBeenCalledTimes(1);
+    } finally {
+      // Restore console.error
+      console.error = originalConsoleError;
+    }
+  });
+});