Write env variable for min version (#151)

.github/actions/install-minimums/action.yml

@@ -40,4 +40,6 @@ runs:
           pip check
           pip list
           echo "::endgroup::"
+        else
+          echo "PIP_CONSTRAINT=${{inputs.constraints_file_path}}" >> $GITHUB_ENV
         fi

.github/workflows/tests.yml

@@ -138,7 +138,9 @@ jobs:
           only_create_file: 1
           constraints_file_path: './constraints-test.txt'
       - name: Ensure constraints file
-        run: cat ./constraints-test.txt
+        run: |
+          cat ./constraints-test.txt
+          echo $PIP_CONSTRAINT | grep "constraints-test.txt"
 
   update_snapshots-manual-server:
     runs-on: ubuntu-latest

README.md

@@ -206,10 +206,34 @@ jobs:
           only_create_file: 1
       - name: Run the unit tests
         run: |
-          export PIP_CONSTRAINT="./contraints_file.txt"
           hatch run test:test
 ```
 
+Note that you can run a test against prereleases like the following:
+
+```yaml
+name: Prerelease Dependencies
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+
+jobs:
+  test_prereleases:
+    name: Test Prereleases
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v3
+      - uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
+        with:
+          python_version: "3.11"
+      - name: Run the tests
+        run: |
+          PIP_PRE=1 hatch run test:nowarn || hatch run test:nowarn --lf
+```
+
 ## Test SDist
 
 Use this pair of actions to build an sdist for your package, and then test it