Output build log on testing related integration test failures

In service of tracking down flaky test failures like #1334, dump the
build/test run log when a testing related integration test fails.

Author: plemarquand

src/TestExplorer/TestRunner.ts

@@ -67,6 +67,7 @@ export interface TestRunState {
     errored: vscode.TestItem[];
     unknown: number;
     output: string[];
+    buildConfig: string;
 }
 
 export class TestRunProxy {
@@ -94,6 +95,7 @@ export class TestRunProxy {
             errored: [],
             unknown: 0,
             output: [],
+            buildConfig: "",
         };
     }
 
@@ -118,6 +120,10 @@ export class TestRunProxy {
         this.onTestRunComplete = this.testRunCompleteEmitter.event;
     }
 
+    public setBuildConfiguration(buildConfig: vscode.DebugConfiguration) {
+        this.runState.buildConfig += "\n" + JSON.stringify(buildConfig, null, 2);
+    }
+
     public testRunStarted = () => {
         if (this.runStarted) {
             return;
@@ -589,6 +595,8 @@ export class TestRunner {
                     return this.testRun.runState;
                 }
 
+                this.testRun.setBuildConfiguration(testBuildConfig);
+
                 const outputStream = this.testOutputWritable(TestLibrary.swiftTesting, runState);
 
                 // Watch the pipe for JSONL output and parse the events into test explorer updates.
@@ -623,6 +631,8 @@ export class TestRunner {
                 return this.testRun.runState;
             }
 
+            this.testRun.setBuildConfiguration(testBuildConfig);
+
             // XCTestRuns are started immediately
             this.testRun.testRunStarted();
 
@@ -957,6 +967,8 @@ export class TestRunner {
                         });
                         subscriptions.push(startSession);
 
+                        this.testRun.setBuildConfiguration(config);
+
                         vscode.debug
                             .startDebugging(this.folderContext.workspaceFolder, config)
                             .then(

test/integration-tests/testexplorer/utilities.ts

@@ -160,7 +160,15 @@ export function assertTestResults(
             skipped: (state.skipped ?? []).sort(),
             errored: (state.errored ?? []).sort(),
             unknown: 0,
-        }
+        },
+        `
+        Test run results do not match expected results
+        Build configuration:
+        ${testRun.runState.buildConfig}
+
+        Build Output:
+        ${testRun.runState.output.join("\n")}
+        `
     );
 }