Show setup message when no targets returned from sync

src/test-explorer/resolver.ts

@@ -149,6 +149,7 @@ export class TestResolver implements OnModuleInit, vscode.Disposable {
       parentTest,
       'Loading: waiting for build server connection'
     )
+    parentTest.error = undefined
     const conn = await this.buildServer.getConnection()
 
     updateDescription(parentTest, 'Loading: fetching available targets')
@@ -202,6 +203,25 @@ export class TestResolver implements OnModuleInit, vscode.Disposable {
       relevantParent.children.add(newTest)
     })
 
+    // If no test items were added, show the getting started message as a test message overlaid on the .bazelproject file.
+    // This provides an opportunity for the user to make adjustments and re-sync.
+    if (parentTest.children.size === 0) {
+      // Dummy test run that overlays the getting started message on the .bazelproject file.
+      const run = this.store.testController.createTestRun(
+        new vscode.TestRunRequest()
+      )
+      run.errored(parentTest, new vscode.TestMessage(gettingStartedMessage))
+      run.end()
+
+      // Link in the test explorer tree to set up the project.
+      const encodedFileUri = encodeURIComponent(JSON.stringify(parentTest.uri))
+      const syncFailMessage = new vscode.MarkdownString(
+        `No test targets found. [Setup your project](command:vscode.open?${encodedFileUri})`
+      )
+      syncFailMessage.isTrusted = true
+      parentTest.error = syncFailMessage
+    }
+
     // Replace all children with the newly returned test cases.
     this.condenseTestItems(parentTest)
     updateDescription(parentTest)
@@ -403,3 +423,19 @@ function combineCancelTokens(
   token2?.onCancellationRequested(() => combinedSource.cancel())
   return combinedSource.token
 }
+
+const gettingStartedMessage = new vscode.MarkdownString(
+  `To use the Test Explorer, please configure your project.
+
+  Getting started tips:
+  - Update this file with some paths that include test targets.
+    - Use the directories key to specify by directory
+    - Use the targets key to specify by Bazel target pattern
+  - Ensure that the bazel_binary field in this file matches the path to your Bazel binary.
+  - Re-sync at any time by clicking the $(extensions-refresh) refresh icon at the very top of the testing panel.
+
+  Does it seem like something else went wrong? Check for output [here](command:bazelbsp.showServerOutput).
+  `,
+  true
+)
+gettingStartedMessage.isTrusted = true

src/test-info/test-item-factory.ts

@@ -36,6 +36,7 @@ export class TestItemFactory {
       'Bazel Test Targets',
       uri
     )
+    newTest.range = new vscode.Range(0, 0, 0, 0)
     newTest.canResolveChildren = true
     this.store.testCaseMetadata.set(
       newTest,

src/test/suite/resolver.test.ts

@@ -344,6 +344,30 @@ suite('Test Resolver', () => {
       }
     })
 
+    test('no targets returned', async () => {
+      const root = testCaseStore.testController.createTestItem(
+        'root',
+        'Bazel Test Targets'
+      )
+      testCaseStore.testController.items.add(root)
+      testCaseStore.testCaseMetadata.set(
+        root,
+        new TestCaseInfo(root, undefined, TestItemType.Root)
+      )
+      assert.ok(testCaseStore.testController.resolveHandler)
+
+      // Simulate an empty result from requesting targets.
+      const emptyResult: bsp.WorkspaceBuildTargetsResult = {
+        targets: [],
+      }
+      const sendRequestStub = sandbox
+        .stub(sampleConn, 'sendRequest')
+        .resolves(emptyResult)
+      await testCaseStore.testController.resolveHandler(root)
+      const message = root.error as vscode.MarkdownString
+      assert.ok(message.value.includes('No test targets found'))
+    })
+
     test('source files within a target', async () => {
       const buildTarget = sampleBuildTargetsResult.targets[0]
       const sendRequestStub = sandbox