Introduce watch method for test files

Because we're no longer running `gulp` when we run our test command,
we're going to need a way to update our test files when they change.

This will watch for any changes in our test files and copy the new
version over.

Co-authored-by: Andrew Eisenberg <aeisenberg@github.com>

extensions/ql-vscode/gulpfile.ts/index.ts

@@ -1,7 +1,7 @@
 import * as gulp from 'gulp';
 import { compileTypeScript, watchTypeScript, cleanOutput } from './typescript';
 import { compileTextMateGrammar } from './textmate';
-import { copyTestData } from './tests';
+import { copyTestData, watchTestData } from './tests';
 import { compileView, watchView } from './webpack';
 import { packageExtension } from './package';
 import { injectAppInsightsKey } from './appInsights';
@@ -21,6 +21,7 @@ export {
   watchView,
   compileTypeScript,
   copyTestData,
+  watchTestData,
   injectAppInsightsKey,
   compileView,
 };

extensions/ql-vscode/gulpfile.ts/tests.ts

@@ -6,6 +6,10 @@ export function copyTestData() {
   return Promise.resolve();
 }
 
+export function watchTestData() {
+  return gulp.watch(['src/vscode-tests/no-workspace/data/**/*', 'src/vscode-tests/minimal-workspace/data/**/*'], copyTestData);
+}
+
 function copyNoWorkspaceData() {
   return gulp.src('src/vscode-tests/no-workspace/data/**/*')
     .pipe(gulp.dest('out/vscode-tests/no-workspace/data'));

extensions/ql-vscode/package.json

@@ -1253,6 +1253,7 @@
     "watch": "npm-run-all -p watch:*",
     "watch:extension": "tsc --watch",
     "watch:webpack": "gulp watchView",
+    "watch:files": "gulp watchTestData",
     "test": "npm-run-all -p test:*",
     "test:unit": "mocha --config .mocharc.json test/pure-tests/**/*.ts",
     "test:view": "jest",