fix: support coverage preview in Vitest 3 (#771)

Author: sheremet-va

.vscode/launch.json

@@ -9,7 +9,11 @@
       "name": "Run Extension Basic Sample",
       "type": "extensionHost",
       "request": "launch",
-      "args": ["--extensionDevelopmentPath=${workspaceFolder}", "${workspaceFolder}/samples/basic"],
+      "args": [
+        "--disable-extensions",
+        "--extensionDevelopmentPath=${workspaceFolder}",
+        "${workspaceFolder}/samples/basic"
+      ],
       "outFiles": ["${workspaceFolder}/dist/**/*.js"]
     },
     {

packages/worker-legacy/src/reporter.ts

@@ -183,7 +183,7 @@ export class VSCodeReporter implements Reporter {
   async onFinished(
     files?: RunnerTestFile[],
     errors: unknown[] = this.vitest.state.getUnhandledErrors(),
-    coverage?: unknown,
+    coverage?: any,
   ) {
     const collecting = this.collecting
 
@@ -214,7 +214,12 @@ export class VSCodeReporter implements Reporter {
     }
 
     nextTick(() => {
-      this.rpc.onTestRunEnd(files || [], output, collecting, coverage)
+      this.rpc.onTestRunEnd(
+        files || [],
+        output,
+        collecting,
+        coverage ? coverage.toJSON() : undefined,
+      )
     })
   }
 

packages/worker-legacy/src/worker.ts

@@ -141,6 +141,10 @@ export class ExtensionWorker implements ExtensionWorkerTransport {
   ) {
     // @ts-expect-error private method in Vitest <=2.1.5
     await this.vitest.initBrowserProviders?.()
+    if (this.vitest.config.coverage.enabled) {
+      await (this.vitest as any).initCoverageProvider?.()
+      await (this.vitest as any).coverageProvider?.clean(this.vitest.config.coverage.clean)
+    }
 
     const specs = await this.resolveTestSpecs(specsOrPaths)