fix(coverage): thresholdAutoUpdate to detect zero limits (#4287)

packages/vitest/src/utils/coverage.ts

@@ -30,7 +30,7 @@ export class BaseCoverageProvider {
     const thresholdsToUpdate: [Threshold, number][] = []
 
     for (const key of THRESHOLD_KEYS) {
-      const threshold = thresholds[key] || 100
+      const threshold = thresholds[key] ?? 100
       const actual = Math.min(...summaries.map(summary => summary[key].pct))
 
       if (actual > threshold)
@@ -45,7 +45,7 @@ export class BaseCoverageProvider {
 
     for (const [threshold, newValue] of thresholdsToUpdate) {
       // Find the exact match from the configuration file and replace the value
-      const previousThreshold = (thresholds[threshold] || 100).toString()
+      const previousThreshold = (thresholds[threshold] ?? 100).toString()
       const pattern = new RegExp(`(${threshold}\\s*:\\s*)${previousThreshold.replace('.', '\\.')}`)
       const matches = originalConfig.match(pattern)
 

test/coverage-test/coverage-report-tests/generic.report.test.ts

@@ -75,12 +75,14 @@ test('thresholdAutoUpdate updates thresholds', async () => {
     const match = configContents.match(new RegExp(`${threshold}: (?<coverage>[\\d|\\.]+)`))
     const coverage = match?.groups?.coverage || '0'
 
-    // Configuration has fixed value of 1.01 set for each threshold
+    // Configuration has fixed value of 1.01 and 0 set for each threshold
     expect(Number.parseInt(coverage)).toBeGreaterThan(1.01)
   }
 
   // Update thresholds back to fixed values
-  const updatedConfig = configContents.replace(/(branches|functions|lines|statements): ([\d|\.])+/g, '$1: 1.01')
+  const updatedConfig = configContents
+    .replace(/(branches|statements): ([\d|\.])+/g, '$1: 1.01')
+    .replace(/(functions|lines): ([\d|\.])+/g, '$1: 0')
   fs.writeFileSync(configFilename, updatedConfig)
 })
 

test/coverage-test/vitest.config.ts

@@ -83,9 +83,9 @@ export default defineConfig({
 
       // These will be updated by tests and reseted back by generic.report.test.ts
       thresholdAutoUpdate: true,
-      functions: 1.01,
+      functions: 0,
       branches: 1.01,
-      lines: 1.01,
+      lines: 0,
       statements: 1.01,
     },
     setupFiles: [