Pass dockerfile to build executor (#1606)

This allows testing actions with non standard dockerfile names

Signed-off-by: Aidan Jensen <aidan@artificial.com>

pkg/runner/action.go

@@ -231,7 +231,7 @@ func execAsDocker(ctx context.Context, step actionStep, actionName string, based
 		image = fmt.Sprintf("%s-dockeraction:%s", regexp.MustCompile("[^a-zA-Z0-9]").ReplaceAllString(actionName, "-"), "latest")
 		image = fmt.Sprintf("act-%s", strings.TrimLeft(image, "-"))
 		image = strings.ToLower(image)
-		contextDir, _ := filepath.Split(filepath.Join(basedir, action.Runs.Image))
+		contextDir, fileName := filepath.Split(filepath.Join(basedir, action.Runs.Image))
 
 		anyArchExists, err := container.ImageExistsLocally(ctx, image, "any")
 		if err != nil {
@@ -261,6 +261,7 @@ func execAsDocker(ctx context.Context, step actionStep, actionName string, based
 			}
 			prepImage = container.NewDockerBuildExecutor(container.NewDockerBuildExecutorInput{
 				ContextDir: contextDir,
+				Dockerfile: fileName,
 				ImageTag:   image,
 				Container:  actionContainer,
 				Platform:   rc.Config.ContainerArchitecture,

pkg/runner/testdata/actions-environment-and-context-tests/push.yml

@@ -11,3 +11,5 @@ jobs:
       - uses: './actions-environment-and-context-tests/docker'
       - uses: 'nektos/act-test-actions/js@main'
       - uses: 'nektos/act-test-actions/docker@main'
+      - uses: 'nektos/act-test-actions/docker-file@main'
+      - uses: 'nektos/act-test-actions/docker-relative-context/action@main'