Integration tests for the content linter (#58547)

Co-authored-by: Copilot <[email protected]>

Author: sarahs

src/content-linter/tests/integration/lint-cli.ts

@@ -0,0 +1,150 @@
+/**
+ * Integration tests for the content linter CLI script.
+ *
+ * These tests verify the actual end-to-end behavior of the lint-content script
+ * by running it via npm commands and checking the output. Unlike unit tests that
+ * test individual functions in isolation, these tests catch issues in the full
+ * CLI workflow including:
+ *
+ * - Command-line argument parsing
+ * - File discovery and processing logic
+ * - Rule configuration and filtering
+ * - Error reporting and exit codes
+ *
+ * Test file structure:
+ * - Test files are created in content/test-integration/ during tests
+ * - This ensures the linter actually processes them (it only processes files in content/ or data/)
+ * - Files are cleaned up after each test
+ *
+ * These tests serve as regression protection and verify that the linter
+ * continues to work as expected when changes are made to the CLI logic.
+ */
+
+import { execSync } from 'child_process'
+import { beforeEach, afterEach, describe, test, expect } from 'vitest'
+import fs from 'fs/promises'
+import path from 'path'
+
+const rootDir = path.join(__dirname, '../../../..')
+const testContentDir = path.join(rootDir, 'content/test-integration')
+
+describe('Content Linter CLI Integration Tests', () => {
+  // Run all tests in sequence to avoid npm process conflicts
+  beforeEach(async () => {
+    // Create test directory
+    await fs.mkdir(testContentDir, { recursive: true })
+  })
+
+  afterEach(async () => {
+    // Clean up test files
+    await fs.rm(testContentDir, { recursive: true, force: true })
+  })
+
+  // Helper function to run linter commands
+  async function runLinter(args: string): Promise<{ output: string; exitCode: number }> {
+    let output = ''
+    let exitCode = 0
+
+    try {
+      output = execSync(`npm run lint-content -- ${args}`, {
+        encoding: 'utf8',
+        cwd: rootDir,
+        stdio: 'pipe',
+        timeout: 10000, // 10 second timeout
+      })
+    } catch (error: any) {
+      output = error.stdout + error.stderr
+      exitCode = error.status || 1
+    }
+
+    return { output, exitCode }
+  }
+
+  describe('Linter functionality verification', () => {
+    test('should detect errors when explicitly running search-replace rule', async () => {
+      // Baseline test - ensures the linter can detect errors
+      const testFile = path.join(testContentDir, 'baseline-test.md')
+      const testContent = `---
+title: Baseline Test
+shortTitle: TODOCS This should definitely be caught
+intro: Testing basic linter functionality
+versions:
+  feature: test
+topics:
+  - Test
+---
+
+TODOCS This placeholder should definitely be detected.
+`
+
+      await fs.writeFile(testFile, testContent)
+
+      const { output, exitCode } = await runLinter(`--paths "${testFile}" --rules search-replace`)
+
+      // This MUST work - if it doesn't, the linter is completely broken
+      expect(exitCode).toBe(1)
+      expect(output).toContain('todocs-placeholder')
+      expect(output).toContain('ERROR')
+    })
+  })
+
+  describe('Default linter behavior', () => {
+    test('should verify default rule execution behavior', async () => {
+      // This test verifies that all rules run by default when no --rules are specified
+      // It serves as regression protection against the TODOCS bug where no rules would run
+      const testFile = path.join(testContentDir, 'default-behavior-test.md')
+      const testContent = `---
+title: Test Article
+shortTitle: TODOCS Test title
+intro: This is a test article
+versions:
+  feature: test
+topics:
+  - Test
+---
+
+TODOCS This is placeholder content that should now be detected by default.
+
+### This heading skips H2 which should be a heading-increment error
+
+`
+
+      await fs.writeFile(testFile, testContent)
+
+      const { output, exitCode } = await runLinter(`--paths "${testFile}"`)
+
+      // Verify that the linter properly detects errors when no --rules are specified
+      expect(exitCode).toBe(1) // Should exit with error due to TODOCS
+      expect(output).toContain('todocs-placeholder') // TODOCS should be detected by default
+      expect(output).toContain('ERROR') // Errors should be detected
+    })
+
+    test('should respect rule filtering when specific rules are provided', async () => {
+      const testFile = path.join(testContentDir, 'multi-error-file.md')
+      const testContent = `---
+title: Test Article
+shortTitle: TODOCS Test title
+intro: This is a test article
+versions:
+  feature: test
+topics:
+  - Test
+---
+
+TODOCS This file has multiple error types.
+
+### This heading skips H2 (heading-increment error)
+`
+
+      await fs.writeFile(testFile, testContent)
+
+      const { output, exitCode } = await runLinter(
+        `--paths "${testFile}" --rules heading-increment`,
+      )
+
+      expect(exitCode).toBe(0) // heading-increment rule behavior with filtering
+      expect(output).not.toContain('ERROR')
+      expect(output).not.toContain('todocs-placeholder')
+    })
+  })
+})