add mermaid exporter test

Author: spdeepak

exporters/mermaid_test.go

@@ -14,10 +14,10 @@ import (
 	"github.com/spdeepak/flowtracker"
 )
 
-func NewServer() http.Handler {
+func NewServer(orientation Orientation, tags []string) http.Handler {
 	mux := http.NewServeMux()
 	mux.HandleFunc("/", Handler)
-	mw := flowtracker.NewMiddleware(flowtracker.WithExporter(&MermaidExporter{}))
+	mw := flowtracker.NewMiddleware(flowtracker.WithExporter(&MermaidExporter{Orientation: orientation, IncludeTags: tags}))
 	return mw(mux)
 }
 
@@ -27,7 +27,7 @@ func TestMermaidExporter_OK(t *testing.T) {
 	r, w, _ := os.Pipe()
 	os.Stdout = w
 
-	server := NewServer()
+	server := NewServer(TopDown, []string{})
 
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
 	rr := httptest.NewRecorder()
@@ -90,6 +90,75 @@ func TestMermaidExporter_OK(t *testing.T) {
 	}
 }
 
+func TestMermaidExporter_OK_IncludeTags(t *testing.T) {
+	// capture stdout
+	old := os.Stdout
+	r, w, _ := os.Pipe()
+	os.Stdout = w
+
+	server := NewServer(LeftRight, []string{"db.query"})
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	rr := httptest.NewRecorder()
+
+	server.ServeHTTP(rr, req)
+
+	time.Sleep(1 * time.Second)
+
+	// restore stdout
+	w.Close()
+	os.Stdout = old
+
+	// read logs
+	var buf bytes.Buffer
+	_, err := io.Copy(&buf, r)
+	if err != nil {
+		t.Error("Error should be nil")
+	}
+
+	logs := buf.String()
+	output := strings.Split(logs, "\n")
+	if !strings.Contains(output[1], "----- MERMAID OUTPUT -----") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.EqualFold(output[2], "```mermaid") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.EqualFold(output[3], "graph LR") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.Contains(output[4], "[\"GET /\"] -->|") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.Contains(output[4], "[\"Process Payment\"]") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.Contains(output[5], "[\"GET /\"] -->|") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.Contains(output[5], "[\"DB: Select User (db.query:SELECT * FROM users...)\"]") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.Contains(output[6], "[\"GET /\"] -->|") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.Contains(output[6], "[\"HTTP: Shipping Service\"]") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.Contains(output[7], "[\"HTTP: Shipping Service\"] -->|") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.Contains(output[7], "[\"Calculate Weight\"]") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.EqualFold(output[8], "```") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+	if !strings.EqualFold(output[9], "--------------------------") {
+		t.Fatalf("expected log not found: %s", logs)
+	}
+}
+
 func Handler(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()