Add WithMaxAPIVersion Option to NginxClient (#380)

* Added WithMaxAPIVersion option to NewNginxClient so that the Max API version can be set by a function

Author: aphralG

Diff for: .gitignore

@@ -5,4 +5,7 @@
 # Visual Studio Code settings
 .vscode
 
+# Goland settings
+.idea/
+
 dist

Diff for: client/nginx.go

@@ -588,6 +588,19 @@ func WithCheckAPI() Option {
 	}
 }
 
+// WithMaxAPIVersion sets the API version to the max API version.
+func WithMaxAPIVersion() Option {
+	return func(o *NginxClient) {
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+		version, err := o.GetMaxAPIVersion(ctx)
+		if err != nil {
+			return
+		}
+		o.apiVersion = version
+	}
+}
+
 // NewNginxClient creates a new NginxClient.
 func NewNginxClient(apiEndpoint string, opts ...Option) (*NginxClient, error) {
 	c := &NginxClient{

Diff for: client/nginx_test.go

@@ -601,6 +601,69 @@ func TestClientWithHTTPClient(t *testing.T) {
 	}
 }
 
+func TestClientWithMaxAPI(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name        string
+		apiVersions string
+		expected    int
+	}{
+		{
+			name:        "Test 1: API versions contains invalid version",
+			apiVersions: `[4, 5, 6, 7, 8, 9, 25]`,
+			expected:    APIVersion,
+		},
+		{
+			name:        "Test 2: No API versions, default API Version is used",
+			apiVersions: ``,
+			expected:    APIVersion,
+		},
+		{
+			name:        "Test 3: API version lower than default",
+			apiVersions: `[4, 5, 6, 7]`,
+			expected:    7,
+		},
+		{
+			name:        "Test 4: No API versions, default API version is used",
+			apiVersions: `[""]`,
+			expected:    APIVersion,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			// Test creating a new client with max API version
+			ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				switch {
+				case r.RequestURI == "/":
+					_, err := w.Write([]byte(tt.apiVersions))
+					if err != nil {
+						t.Fatalf("unexpected error: %v", err)
+					}
+				default:
+					_, err := w.Write([]byte(`{}`))
+					if err != nil {
+						t.Fatalf("unexpected error: %v", err)
+					}
+				}
+			}))
+			defer ts.Close()
+
+			client, err := NewNginxClient(ts.URL, WithMaxAPIVersion())
+			if err != nil {
+				t.Fatalf("unexpected error: %v", err)
+			}
+			if client == nil {
+				t.Fatalf("client is nil")
+			}
+			if client.apiVersion != tt.expected {
+				t.Fatalf("expected client.apiVersion to be %v, but got %v", tt.expected, client.apiVersion)
+			}
+		})
+	}
+}
+
 func TestGetStats_NoStreamEndpoint(t *testing.T) {
 	var writeLock sync.Mutex