Add integration tests

This patch adds a simple integration test run on GitHub Actions. This is
running the exporter and checking that metrics exists and values are
properly read.

.github/workflows/lint.yml

@@ -1,9 +1,9 @@
-name: bandit and flake8
+name: Linting
 
 on:
   push:
     branches-ignore:
-      - 'dependabot/**'
+      - "dependabot/**"
   pull_request:
 
 jobs:
@@ -14,11 +14,11 @@ jobs:
         # https://endoflife.date/python
         # https://github.com/actions/runner-images
         python-version:
-          - '3.9'
-          - '3.10'
-          - '3.11'
-          - '3.12'
-          - '3.13'
+          - "3.9"
+          - "3.10"
+          - "3.11"
+          - "3.12"
+          - "3.13"
 
     steps:
       - uses: actions/checkout@v4

.github/workflows/test.yml

@@ -0,0 +1,69 @@
+name: Integration tests
+
+on:
+  push:
+    branches-ignore:
+      - "dependabot/**"
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # https://endoflife.date/python
+        # https://github.com/actions/runner-images/blob/main/images/linux/Ubuntu2204-Readme.md#python
+        python-version:
+          - "3.9"
+          - "3.10"
+          - "3.11"
+          - "3.12"
+          - "3.13"
+
+    steps:
+      - name: start mongodb
+        run: docker run --name mongo -p 127.0.0.1:27017:27017 -d mongo:latest
+
+      - uses: actions/checkout@v4
+
+      - name: set up python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - run: pip install -r requirements.txt
+
+      - run: pip install flake8 bandit
+
+      - name: add test data to mongodb
+        run: |
+          echo 'db.messages.insertOne({
+              user: "John Doe",
+              createdAt: ISODate("3025-01-15T21:31:09.989Z"),
+              updatedAt: ISODate("3025-01-15T21:31:09.989Z")
+            });
+            db.users.insertOne({
+              username: "jdoe"
+            });
+            quit;' | docker exec -i mongo mongosh LibreChat
+
+      - name: run exporter
+        env:
+          MONGODB_URI: "mongodb://127.0.0.1:27017/"
+        run: python metrics.py &> exporter.log &
+
+      - name: get metrics
+        run: >
+          curl -fisS --retry 60 --retry-delay 1 --retry-all-errors
+          http://localhost:8000 -o metrics
+
+      - name: show metrics
+        if: ${{ always() }}
+        run: cat metrics
+
+      - name: show log
+        if: ${{ always() }}
+        run: cat exporter.log
+
+      - name: probe for valid output
+        run: grep 'librechat_users_total 1.0' metrics