add test and example

vertexai/genai/client_test.go

@@ -59,6 +59,22 @@ func TestLive(t *testing.T) {
 		got := responseString(resp)
 		checkMatch(t, got, `15.* cm|[1-9].* inches`)
 	})
+	t.Run("system-instructions", func(t *testing.T) {
+		t.Skip("feature not yet available")
+		model := client.GenerativeModel(*modelName)
+		model.Temperature = Ptr[float32](0)
+		model.SystemInstruction = &Content{
+			Parts: []Part{Text("You are Yoda from Star Wars.")},
+		}
+		resp, err := model.GenerateContent(ctx, Text("What is the average size of a swallow?"))
+		if err != nil {
+			t.Fatal(err)
+		}
+		got := responseString(resp)
+		checkMatch(t, got, `15.* cm|[1-9].* inches`)
+		fmt.Println(got)
+
+	})
 
 	t.Run("streaming", func(t *testing.T) {
 		iter := model.GenerateContentStream(ctx, Text("Are you hungry?"))

vertexai/genai/example_test.go

@@ -51,6 +51,31 @@ func ExampleGenerativeModel_GenerateContent() {
 	printResponse(resp)
 }
 
+// This example shows how to a configure a model. See [GenerationConfig]
+// for the complete set of configuration options.
+func ExampleGenerativeModel_GenerateContent_config() {
+	ctx := context.Background()
+	client, err := genai.NewClient(ctx, option.WithAPIKey(os.Getenv("GEMINI_API_KEY")))
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer client.Close()
+
+	model := client.GenerativeModel("gemini-1.0-pro")
+	model.SetTemperature(0.9)
+	model.SetTopP(0.5)
+	model.SetTopK(20)
+	model.SetMaxOutputTokens(100)
+	model.SystemInstruction = &genai.Content{
+		Parts: []genai.Part{genai.Text("You are Yoda from Star Wars.")},
+	}
+	resp, err := model.GenerateContent(ctx, genai.Text("What is the average size of a swallow?"))
+	if err != nil {
+		log.Fatal(err)
+	}
+	printResponse(resp)
+}
+
 func ExampleGenerativeModel_GenerateContentStream() {
 	ctx := context.Background()
 	client, err := genai.NewClient(ctx, projectID, location)