chore(tests): Add unit tests to image-updater pkg/health, pkg/version and pkg/registry (argoproj-labs#771)

Signed-off-by: Mangaal <[email protected]>

Author: Mangaal

pkg/health/health_test.go

@@ -0,0 +1,52 @@
+package health
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+)
+
+// Unit test function
+func TestStartHealthServer_InvalidPort(t *testing.T) {
+	// Use an invalid port number
+	port := -1
+	errCh := StartHealthServer(port)
+	defer close(errCh) // Close the error channel after the test completes
+	select {
+	case err := <-errCh:
+		if err == nil {
+			t.Error("Expected error, got nil")
+		} else if err.Error() != fmt.Sprintf("listen tcp: address %d: invalid port", port) {
+			t.Errorf("Expected error message about invalid port, got %v", err)
+		}
+	case <-time.After(2 * time.Second):
+		t.Error("Timed out waiting for error")
+	}
+}
+
+func TestHealthProbe(t *testing.T) {
+	// Create a mock HTTP request
+	req, err := http.NewRequest("GET", "/healthz", nil)
+	if err != nil {
+		t.Fatalf("Failed to create request: %v", err)
+	}
+
+	// Create a mock HTTP response recorder
+	w := httptest.NewRecorder()
+
+	// Call the HealthProbe function directly
+	HealthProbe(w, req)
+
+	// Check the response status code
+	if w.Code != http.StatusOK {
+		t.Errorf("Expected status OK; got %d", w.Code)
+	}
+
+	// Check the response body
+	expectedBody := "OK\n"
+	if body := w.Body.String(); body != expectedBody {
+		t.Errorf("Expected body %q; got %q", expectedBody, body)
+	}
+}