Merge #7799

7799: Related tests r=matklad a=vsrs

![tests](https://user-images.githubusercontent.com/62505555/109397453-a9013680-7947-11eb-8b11-ac03079f7645.gif)
This adds an ability to look for tests for the item under the cursor: function, constant, data type, etc

The LSP part is bound to change. But the feature itself already works and I'm looking for a feedback :)



Co-authored-by: vsrs <vit@conrlab.com>

editors/code/src/commands.ts

@@ -9,6 +9,7 @@ import { RunnableQuickPick, selectRunnable, createTask, createArgs } from './run
 import { AstInspector } from './ast_inspector';
 import { isRustDocument, sleep, isRustEditor } from './util';
 import { startDebugSession, makeDebugConfig } from './debug';
+import { LanguageClient } from 'vscode-languageclient/node';
 
 export * from './ast_inspector';
 export * from './run';
@@ -455,17 +456,20 @@ export function reloadWorkspace(ctx: Ctx): Cmd {
     return async () => ctx.client.sendRequest(ra.reloadWorkspace);
 }
 
+async function showReferencesImpl(client: LanguageClient, uri: string, position: lc.Position, locations: lc.Location[]) {
+    if (client) {
+        await vscode.commands.executeCommand(
+            'editor.action.showReferences',
+            vscode.Uri.parse(uri),
+            client.protocol2CodeConverter.asPosition(position),
+            locations.map(client.protocol2CodeConverter.asLocation),
+        );
+    }
+}
+
 export function showReferences(ctx: Ctx): Cmd {
     return async (uri: string, position: lc.Position, locations: lc.Location[]) => {
-        const client = ctx.client;
-        if (client) {
-            await vscode.commands.executeCommand(
-                'editor.action.showReferences',
-                vscode.Uri.parse(uri),
-                client.protocol2CodeConverter.asPosition(position),
-                locations.map(client.protocol2CodeConverter.asLocation),
-            );
-        }
+        await showReferencesImpl(ctx.client, uri, position, locations);
     };
 }
 
@@ -554,6 +558,36 @@ export function run(ctx: Ctx): Cmd {
     };
 }
 
+export function peekTests(ctx: Ctx): Cmd {
+    const client = ctx.client;
+
+    return async () => {
+        const editor = ctx.activeRustEditor;
+        if (!editor || !client) return;
+
+        await vscode.window.withProgress({
+            location: vscode.ProgressLocation.Notification,
+            title: "Looking for tests...",
+            cancellable: false,
+        }, async (_progress, _token) => {
+            const uri = editor.document.uri.toString();
+            const position = client.code2ProtocolConverter.asPosition(
+                editor.selection.active,
+            );
+
+            const tests = await client.sendRequest(ra.relatedTests, {
+                textDocument: { uri: uri },
+                position: position,
+            });
+            const locations: lc.Location[] = tests.map(it =>
+                lc.Location.create(it.runnable.location!.targetUri, it.runnable.location!.targetSelectionRange));
+
+            await showReferencesImpl(client, uri, position, locations);
+        });
+    };
+}
+
+
 export function runSingle(ctx: Ctx): Cmd {
     return async (runnable: ra.Runnable) => {
         const editor = ctx.activeRustEditor;