Improved testing process.exit calls 🚪

jest-config/setup.ts

@@ -3,6 +3,10 @@ jest.mock('log-symbols', () => ({
   error: 'X',
 }))
 
+jest.spyOn(process, 'exit').mockImplementation(code => {
+  throw new Error(`process.exit(${code})`)
+})
+
 beforeEach(() => {
   global.debug = false
 })

src/__tests__/sourceFiles.spec.ts

@@ -11,7 +11,6 @@ describe('sourceFiles', () => {
 
   jest.spyOn(colourLog, 'configDebug').mockImplementation(() => {})
   jest.spyOn(colourLog, 'error').mockImplementation(() => {})
-  jest.spyOn(process, 'exit').mockImplementation(() => null as never)
 
   const commonArgs = {
     filePattern: '*.ts',
@@ -54,14 +53,18 @@ describe('sourceFiles', () => {
   })
 
   it('catches any errors and exists the process', async () => {
+    expect.assertions(2)
+
     const error = new Error('Test error')
 
     jest.mocked(glob).mockRejectedValue(error)
 
-    await sourceFiles(commonArgs)
-
-    expect(colourLog.error).toHaveBeenCalledWith('An error occurred while trying to source files matching *.ts', error)
-    expect(process.exit).toHaveBeenCalledWith(1)
+    try {
+      await sourceFiles(commonArgs)
+    } catch {
+      expect(colourLog.error).toHaveBeenCalledWith('An error occurred while trying to source files matching *.ts', error)
+      expect(process.exit).toHaveBeenCalledWith(1)
+    }
   })
 
 })

src/index.ts

@@ -111,4 +111,8 @@ program
     }
   })
 
+process.on('exit', () => {
+  console.log()
+})
+
 program.parse(process.argv)

src/linters/eslint.ts

@@ -13,21 +13,21 @@ const lintFiles = async (files: Array<string>): Promise<LintReport> => {
       fix: false,
     })
 
-    const results: Array<ESLint.LintResult> = await eslint.lintFiles(files)
+    const lintResults: Array<ESLint.LintResult> = await eslint.lintFiles(files)
 
     const reportResults: ReportResults = {}
 
     const reportSummary: ReportSummary = {
       deprecatedRules: [],
       errorCount: 0,
-      fileCount: results.length,
+      fileCount: lintResults.length,
       fixableErrorCount: 0,
       fixableWarningCount: 0,
       linter: Linter.ESLint,
       warningCount: 0,
     }
 
-    results.forEach(({ errorCount, filePath, fixableErrorCount, fixableWarningCount, messages, usedDeprecatedRules, warningCount }) => {
+    lintResults.forEach(({ errorCount, filePath, fixableErrorCount, fixableWarningCount, messages, usedDeprecatedRules, warningCount }) => {
       const file = filePath.replace(`${process.cwd()}/`, '')
 
       reportSummary.deprecatedRules = [...new Set([...reportSummary.deprecatedRules, ...usedDeprecatedRules.map(({ ruleId }) => ruleId)])]
@@ -57,7 +57,6 @@ const lintFiles = async (files: Array<string>): Promise<LintReport> => {
     }
   } catch (error: any) {
     colourLog.error('An error occurred while running eslint', error)
-    console.log()
     process.exit(1)
   }
 }

src/linters/markdownlint/__tests__/index.spec.ts

@@ -45,26 +45,40 @@ describe('markdownlint', () => {
     }, expect.any(Function))
   })
 
-  it('rejects when markdownlint returns an error', async () => {
+  it('exists the process when markdownlint returns an error', async () => {
+    expect.assertions(2)
+
     const error = new Error('Test error')
 
     jest.mocked(markdownlint).mockImplementationOnce((_options, callback) => {
       callback(error, undefined)
     })
 
-    await expect(markdownlintLib.lintFiles(testFiles)).rejects.toThrow(error)
-
-    expect(colourLog.error).toHaveBeenCalledOnceWith('An error occurred while running markdownlint', error)
+    try {
+      await markdownlintLib.lintFiles(testFiles)
+    } catch {
+      expect(colourLog.error).toHaveBeenCalledOnceWith('An error occurred while running markdownlint', error)
+      expect(process.exit).toHaveBeenCalledWith(1)
+    }
   })
 
-  it('rejects when markdownlint returns no results', async () => {
+  it('resolves with results and a summary when markdownlint successfully lints (no files)', async () => {
     jest.mocked(markdownlint).mockImplementationOnce((_options, callback) => {
       callback(null, undefined)
     })
 
-    await expect(markdownlintLib.lintFiles(testFiles)).rejects.toThrow('No results')
-
-    expect(colourLog.error).toHaveBeenCalledOnceWith('An error occurred while running markdownlint: no results')
+    expect(await markdownlintLib.lintFiles([])).toStrictEqual({
+      results: {},
+      summary: {
+        deprecatedRules: [],
+        errorCount: 0,
+        fileCount: 0,
+        fixableErrorCount: 0,
+        fixableWarningCount: 0,
+        linter: 'MarkdownLint',
+        warningCount: 0,
+      },
+    })
   })
 
   it('resolves with results and a summary when markdownlint successfully lints (no errors)', async () => {

src/linters/markdownlint/__tests__/loadConfig.spec.ts

@@ -12,7 +12,6 @@ describe('loadConfig', () => {
 
   jest.spyOn(colourLog, 'error').mockImplementation(() => {})
   jest.spyOn(markdownlint, 'readConfigSync').mockImplementation(() => ({ default: true }))
-  jest.spyOn(process, 'exit').mockImplementation(() => null as never)
 
   it('returns the custom config if it exists', () => {
     jest.mocked(fs.existsSync).mockReturnValueOnce(true)
@@ -46,16 +45,20 @@ describe('loadConfig', () => {
   })
 
   it('catches and logs any errors', () => {
+    expect.assertions(2)
+
     const error = new Error('Test error')
 
     jest.mocked(fs.existsSync).mockImplementationOnce(() => {
       throw error
     })
 
-    loadConfig()
-
-    expect(colourLog.error).toHaveBeenCalledWith('An error occurred while loading the markdownlint config', error)
-    expect(process.exit).toHaveBeenCalledWith(1)
+    try {
+      loadConfig()
+    } catch {
+      expect(colourLog.error).toHaveBeenCalledWith('An error occurred while loading the markdownlint config', error)
+      expect(process.exit).toHaveBeenCalledWith(1)
+    }
   })
 
 })

src/linters/markdownlint/index.ts

@@ -16,30 +16,25 @@ const lintFiles = (files: Array<string>): Promise<LintReport> => new Promise((re
   markdownlint({
     config,
     files,
-  }, (error: any, results: LintResults | undefined) => {
+  }, (error: any, lintResults: LintResults | undefined = {}) => {
     if (error) {
       colourLog.error('An error occurred while running markdownlint', error)
-      return reject(error)
-    }
-
-    if (!results) {
-      colourLog.error('An error occurred while running markdownlint: no results')
-      return reject(new Error('No results'))
+      process.exit(1)
     }
 
     const reportResults: ReportResults = {}
 
     const reportSummary: ReportSummary = {
       deprecatedRules: [],
       errorCount: 0,
-      fileCount: Object.keys(results).length,
+      fileCount: Object.keys(lintResults).length,
       fixableErrorCount: 0,
       fixableWarningCount: 0,
       linter: Linter.Markdownlint,
       warningCount: 0,
     }
 
-    Object.entries(results).forEach(([file, errors]) => {
+    Object.entries(lintResults).forEach(([file, errors]) => {
       if (!errors.length) {
         return
       }