tests: Microsoft Windows Server CI (#4791)

Due to a recent release that wasn't functioning properly this CI will help us catch the majority of Microsoft Node Quirks before they make it into a release.

.github/workflows/backend-tests.yml

@@ -4,13 +4,13 @@ name: "Backend tests"
 on: [push, pull_request]
 
 jobs:
-  withoutplugins:
+  withoutpluginsLinux:
     # run on pushes to any branch
     # run on PRs from external forks
     if: |
          (github.event_name != 'pull_request')
          || (github.event.pull_request.head.repo.id != github.event.pull_request.base.repo.id)
-    name: without plugins
+    name: Linux without plugins
     runs-on: ubuntu-latest
 
     steps:
@@ -33,13 +33,13 @@ jobs:
     - name: Run the backend tests
       run: cd src && npm test
 
-  withplugins:
+  withpluginsLinux:
     # run on pushes to any branch
     # run on PRs from external forks
     if: |
          (github.event_name != 'pull_request')
          || (github.event.pull_request.head.repo.id != github.event.pull_request.base.repo.id)
-    name: with Plugins
+    name: Linux with Plugins
     runs-on: ubuntu-latest
 
     steps:
@@ -85,3 +85,87 @@ jobs:
 
     - name: Run the backend tests
       run: cd src && npm test
+
+  withoutpluginsWindows:
+    # run on pushes to any branch
+    # run on PRs from external forks
+    if: |
+         (github.event_name != 'pull_request')
+         || (github.event.pull_request.head.repo.id != github.event.pull_request.base.repo.id)
+    name: Windows without plugins
+    runs-on: windows-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - uses: actions/setup-node@v2
+      with:
+        node-version: 12
+
+    - name: Install all dependencies and symlink for ep_etherpad-lite
+      run: |
+            cd src
+            npm ci --no-optional
+
+    - name:  Fix up the settings.json
+      run: |
+            powershell -Command "(gc settings.json.template) -replace '\"max\": 10', '\"max\": 10000' | Out-File -encoding ASCII settings.json.holder"
+            powershell -Command "(gc settings.json.holder) -replace '\"points\": 10', '\"points\": 1000' | Out-File -encoding ASCII settings.json"
+
+    - name: Run the backend tests
+      run: cd src && npm test
+
+  withpluginsWindows:
+    # run on pushes to any branch
+    # run on PRs from external forks
+    if: |
+         (github.event_name != 'pull_request')
+         || (github.event.pull_request.head.repo.id != github.event.pull_request.base.repo.id)
+    name: Windows with Plugins
+    runs-on: windows-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - uses: actions/setup-node@v2
+      with:
+        node-version: 12
+
+    - name: Install Etherpad plugins
+      run: >
+        npm install
+        ep_align
+        ep_author_hover
+        ep_cursortrace
+        ep_font_size
+        ep_hash_auth
+        ep_headings2
+        ep_image_upload
+        ep_markdown
+        ep_readonly_guest
+        ep_set_title_on_pad
+        ep_spellcheck
+        ep_subscript_and_superscript
+        ep_table_of_contents
+
+    # This must be run after installing the plugins, otherwise npm will try to
+    # hoist common dependencies by removing them from src/node_modules and
+    # installing them in the top-level node_modules. As of v6.14.10, npm's hoist
+    # logic appears to be buggy, because it sometimes removes dependencies from
+    # src/node_modules but fails to add them to the top-level node_modules. Even
+    # if npm correctly hoists the dependencies, the hoisting seems to confuse
+    # tools such as `npm outdated`, `npm update`, and some ESLint rules.
+    - name: Install all dependencies and symlink for ep_etherpad-lite
+      run: |
+            cd src
+            npm ci --no-optional
+
+    - name:  Fix up the settings.json
+      run: |
+            powershell -Command "(gc settings.json.template) -replace '\"max\": 10', '\"max\": 10000' | Out-File -encoding ASCII settings.json.holder"
+            powershell -Command "(gc settings.json.holder) -replace '\"points\": 10', '\"points\": 1000' | Out-File -encoding ASCII settings.json"
+
+    - name: Run the backend tests
+      run: cd src && npm test