Test diff. (#41)

* Test diff.

* Run yarn upgrade.

* Use the right option, document the new option in action.yml.

* Fix revision.

* Smarter example

* Try head_ref.

* Base sha.

* Fix readme.

.github/workflows/test.yml

@@ -68,6 +68,13 @@ jobs:
           api-key: ${{secrets.fossaApiKey}}
           run-tests: true
 
+      - name: Run FOSSA test with --diff
+        uses: ./
+        with:
+          api-key: ${{secrets.fossaApiKey}}
+          run-tests: ${{ github.event_name == 'pull_request' }}
+          test-diff-revision: ${{ github.event.pull_request.base.sha }}
+
       - name: Run FOSSA test with container
         uses: ./
         with:

README.md

@@ -52,6 +52,28 @@ jobs:
           run-tests: true
 ```
 
+## `test-diff-revision`
+**Optional** If set to a string, FOSSA will run the `fossa test` command with the `--diff` [option](https://github.com/fossas/fossa-cli/blob/master/docs/references/subcommands/test.md#test-for-new-issues-compared-to-another-revision).
+
+Setting this field has no effect if `run-tests` is `false`.
+You must also set `run-tests` to `true` in order for this field to take effect.
+
+This example will run fossa test only if the workflow run event is a pull request and verify that there are no new issues relative to the base ref.
+
+```yml
+jobs:
+  fossa-scan:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: fossas/fossa-action@main # Use a specific version if locking is preferred
+        with:
+          api-key: ${{secrets.fossaApiKey}}
+          run-tests: ${{ github.event_name == 'pull_request' }}
+          test-diff-revision: ${{ github.event.pull_request.base.sha }}
+
+```
+
 ### `container`
 **Optional** A container name or OCI image path.  Set to use FOSSA's container scanning functionality. This will run `fossa container analyze` (default behavior) and `fossa container test` (if used in combination with `run-tests`).
 

action.yml

@@ -35,6 +35,11 @@ inputs:
       mode will generate a debug bundle that can be uploaded as a build artifact
       after this action completes.
     default: false
+  test-diff-revision:
+    description: >-
+      Run fossa test with the `--diff <revision>` option, which checks if there are new issues relative to `<revision>`.
+      Requires `run-tests` to be set in order to take effect.
+    required: false
 
 runs:
   using: node20

src/config.ts

@@ -10,6 +10,7 @@ const getInputOptions = (required: boolean = false): InputOptions => ({
 export const FOSSA_API_KEY = getInput('api-key', getInputOptions(true));
 export const CONTAINER = getInput('container', getInputOptions());
 export const RUN_TESTS = getBooleanInput('run-tests', {required: false});
+export const TEST_DIFF_REV = getInput('test-diff-revision', {required: false});
 export const ENDPOINT = getInput('endpoint', getInputOptions());
 export const BRANCH = getInput('branch', getInputOptions());
 export const PROJECT = getInput('project', getInputOptions());

src/index.ts

@@ -4,6 +4,7 @@ import {
   CONTAINER,
   FOSSA_API_KEY,
   RUN_TESTS,
+  TEST_DIFF_REV,
   ENDPOINT,
   BRANCH,
   PROJECT,
@@ -61,7 +62,13 @@ export async function analyze(): Promise<void> {
     }
   } else if (RUN_TESTS) {
     output = '';
-    const exitCode = await exec('fossa', [...getArgs('test'), CONTAINER], defaultOptions);
+    let args = [...getArgs('test'), CONTAINER];
+
+    if (TEST_DIFF_REV && TEST_DIFF_REV !== '') {
+      args.push('--diff', TEST_DIFF_REV);
+    }
+
+    const exitCode = await exec('fossa', args, defaultOptions);
 
     // Check output or exitCode
     if (exitCode !== 0 || output.match(failedRegex)) {