Show Swift test explorer context menu items only for Swift tests (#1048)

Keep a flattened list of swift Test Explorer test IDs in the context and
use a `when` clause on the context menu items to only show them on Swift
tests in the Text Explorer.

Issue: #1047

Author: plemarquand

Diff for: package.json

@@ -616,30 +616,31 @@
         {
           "command": "swift.runTestsMultipleTimes",
           "group": "testExtras",
-          "when": "testId"
+          "when": "testId in swift.tests"
         },
         {
           "command": "swift.runTestsUntilFailure",
           "group": "testExtras",
-          "when": "testId"
+          "when": "testId in swift.tests"
         }
       ],
       "testing/item/context": [
         {
           "command": "swift.runTestsMultipleTimes",
           "group": "testExtras",
-          "when": "testId"
+          "when": "testId in swift.tests"
         },
         {
           "command": "swift.runTestsUntilFailure",
           "group": "testExtras",
-          "when": "testId"
+          "when": "testId in swift.tests"
         }
       ],
       "file/newFile": [
         {
           "command": "swift.newFile",
-          "group": "file"
+          "group": "file",
+          "when": "swift.isActivated"
         }
       ],
       "explorer/context": [

Diff for: src/TestExplorer/TestExplorer.ts

@@ -27,6 +27,7 @@ import * as TestDiscovery from "./TestDiscovery";
 import { TargetType } from "../SwiftPackage";
 import { parseTestsFromSwiftTestListOutput } from "./SPMTestDiscovery";
 import { parseTestsFromDocumentSymbols } from "./DocumentSymbolTestDiscovery";
+import { flattenTestItemCollection } from "./TestUtils";
 
 /** Build test explorer UI */
 export class TestExplorer {
@@ -56,8 +57,6 @@ export class TestExplorer {
         this.controller.resolveHandler = async item => {
             if (!item) {
                 await this.discoverTestsInWorkspace();
-            } else {
-                //
             }
         };
 
@@ -106,6 +105,7 @@ export class TestExplorer {
             this.onTestItemsDidChangeEmitter,
             this.onDidCreateTestRunEmitter,
             ...this.testRunProfiles,
+            this.onTestItemsDidChange(() => this.updateSwiftTestContext()),
         ];
     }
 
@@ -161,7 +161,18 @@ export class TestExplorer {
         });
     }
 
-    /** Called whenever we have new document symbols */
+    /**
+     * Sets the `swift.tests` context variable which is used by commands
+     * to determine if the test item belongs to the Swift extension.
+     */
+    private updateSwiftTestContext() {
+        const items = flattenTestItemCollection(this.controller.items).map(({ id }) => id);
+        vscode.commands.executeCommand("setContext", "swift.tests", items);
+    }
+
+    /**
+     * Called whenever we have new document symbols
+     */
     private static onDocumentSymbols(
         folder: FolderContext,
         document: vscode.TextDocument,

Diff for: src/TestExplorer/TestUtils.ts

@@ -29,3 +29,15 @@ export function reduceTestItemChildren<U>(
     });
     return accumulator;
 }
+
+/**
+ * Returns a flattented, iterable collection of test items in the collection.
+ */
+export function flattenTestItemCollection(coll: vscode.TestItemCollection): vscode.TestItem[] {
+    const items: vscode.TestItem[] = [];
+    coll.forEach(item => {
+        items.push(item);
+        items.push(...flattenTestItemCollection(item.children));
+    });
+    return items;
+}