Add tests for parsing parallel XCTest run output

When performing a parallel XCTest run we first parse the terminal
output, then parse the xUnit XML output and merge the two data sets
together to create the run results. This merging was not being tested at
the unit test level, only at the integration test level, which lead to
a subtle and occasional bug, #1334 (fixed in #1343).

As a followup, update the existing XCTestOutputParser tests to test both
regular and parallel test run output. xUnit XML is synthesized from the
expected results and fed in to the `TestXUnitParser` to modify the
test's `TestRunState` just as it is in the extension.

test/integration-tests/testexplorer/MockTestRunState.ts

@@ -24,8 +24,8 @@ export enum TestStatus {
     skipped = "skipped",
 }
 
-/** TestItem */
-interface TestItem {
+/** TestRunTestItem */
+export interface TestRunTestItem {
     name: string;
     status: TestStatus;
     issues?: {
@@ -40,11 +40,11 @@ interface TestItem {
 
 interface ITestItemFinder {
     getIndex(id: string): number;
-    tests: TestItem[];
+    tests: TestRunTestItem[];
 }
 
 export class DarwinTestItemFinder implements ITestItemFinder {
-    tests: TestItem[] = [];
+    tests: TestRunTestItem[] = [];
     getIndex(id: string): number {
         const index = this.tests.findIndex(item => item.name === id);
         if (index === -1) {
@@ -56,7 +56,7 @@ export class DarwinTestItemFinder implements ITestItemFinder {
 }
 
 export class NonDarwinTestItemFinder implements ITestItemFinder {
-    tests: TestItem[] = [];
+    tests: TestRunTestItem[] = [];
     getIndex(id: string): number {
         const index = this.tests.findIndex(item => item.name.endsWith(id));
         if (index === -1) {
@@ -81,7 +81,7 @@ export class TestRunState implements ITestRunState {
 
     public testItemFinder: ITestItemFinder;
 
-    get tests(): TestItem[] {
+    get tests(): TestRunTestItem[] {
         return this.testItemFinder.tests;
     }