Migrate Backend tests to a GHA workflow

Author: DharmitD

.github/workflows/presubmit-backend.yml

@@ -0,0 +1,30 @@
+name: KFP Backend Tests
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+    paths:
+      - 'backend/**'
+      - 'test/presubmit-backend-test.sh'
+  workflow_dispatch:
+
+jobs:
+  backend-tests:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v2
+
+    - name: Set up Go
+      uses: actions/setup-go@v3
+      with:
+        go-version: '1.21'
+
+    - name: Run Backend Tests
+      run: ./test/presubmit-backend-test.sh
+      shell: bash

test/presubmit-backend-test.sh

@@ -19,15 +19,20 @@ set -ex
 
 # Add installed go binaries to PATH.
 export PATH="${PATH}:$(go env GOPATH)/bin"
-# The current directory is /home/prow/go/src/github.com/kubeflow/pipelines
-cd /home/prow/go/src/github.com/kubeflow/pipelines
+
+# Navigate to the repository root directory
+REPO_ROOT=$(git rev-parse --show-toplevel)
+cd "$REPO_ROOT"
+
 # 1. Check go modules are tidy
 # Reference: https://github.com/golang/go/issues/27005#issuecomment-564892876
 go mod download
 go mod tidy
 git diff --exit-code -- go.mod go.sum || (echo "go modules are not tidy, run 'go mod tidy'." && exit 1)
-# 2. run test in project directory
+
+# 2. Run tests in the backend directory
 go test -v -cover ./backend/...
+
 # 3. Check for forbidden go licenses
 ./hack/install-go-licenses.sh
 go-licenses check ./backend/src/apiserver ./backend/src/cache ./backend/src/agent/persistence ./backend/src/crd/controller/scheduledworkflow ./backend/src/crd/controller/viewer