Fix flaky UI test (#684)

* Make more screenshots to find issue.

* Fix screenshot upload path.

* Error on missing screenshots, indicating wrong path.

* Do not fail-fast OS matrix.

* Update VS Code and extester.

* Wait for synatx highlighting.

* Downgrade VS Code.

* Revert unrelated changes.

* Fix shellcheck warnings.

* Always upload screenshots.

* Await opening resources.

Since 8.17.0, the artificial delay in `openResources` has been removed: redhat-developer/vscode-extension-tester@aba24cc#diff-1af7accc0763e50d55026f156144e4248fd262eb7a6bfddd91851aac41e51ecc

* Revert most changes in preparation of squash.

Author: toinehartman

.github/workflows/build.yaml

@@ -120,8 +120,9 @@ jobs:
         if: failure()
         with:
           name: screenshots-${{ matrix.os }}
-          path: ./rascal-vscode-extension/uitests/**/screenshots/*.png
+          path: ./rascal-vscode-extension/uitests/screenshots/**/*.png
           retention-days: 5
+          if-no-files-found: error
 
       - name: "cleanup before cache"
         shell: bash

rascal-vscode-extension/package-lock.json

@@ -297,7 +297,7 @@ export class IDEOperations {
     }
 
     async openModule(file: string): Promise<TextEditor> {
-        this.browser.openResources(file); // intentionally not waiting, since it sleeps for 3s without anything happening
+        await this.browser.openResources(file);
         return this.driver.wait(async () => {
             const result = await ignoreFails(new Workbench().getEditorView().openEditor(path.basename(file))) as TextEditor;
             if (result && await ignoreFails(result.getTitle()) === path.basename(file)) {

rascal-vscode-extension/src/test/vscode-suite/utils.ts

@@ -1,4 +1,4 @@
-# !/bin/sh
+#!/bin/sh
 
 # This documents (and performs) necessary commands for local UI testing.
 # Experts might run these manually on demand. For example, repeatedly
@@ -20,9 +20,9 @@ rm -rf $UITESTS || true
 npm run compile-tests
 
 # test what was compiled
-VSCODE_VERSION=`grep '"vscode":' package.json | awk -F\^ '{ print $2 }' | awk -F\" '{ print $1 }'`
+VSCODE_VERSION=$(grep '"vscode":' package.json | awk -F^ '{ print $2 }' | awk -F\" '{ print $1 }')
 echo "Running tests with VSCode version $VSCODE_VERSION"
 exec npx extest setup-and-run out/test/vscode-suite/*.test.js \
-    --code_version ${VSCODE_VERSION} \
+    --code_version "${VSCODE_VERSION}" \
     --storage $UITESTS \
     --extensions_dir $UITESTS/extensions_dir