test(api): handler response helpers

internal/api/handlers/responses_test.go

@@ -0,0 +1,81 @@
+package handlers
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestRespond_StatusAndContentType(t *testing.T) {
+	w := httptest.NewRecorder()
+	respond(w, http.StatusOK, map[string]string{"hello": "world"})
+	if w.Code != http.StatusOK {
+		t.Errorf("expected 200, got %d", w.Code)
+	}
+	if ct := w.Header().Get("Content-Type"); ct != "application/json" {
+		t.Errorf("expected application/json, got %s", ct)
+	}
+}
+
+func TestRespond_EncodesJSON(t *testing.T) {
+	w := httptest.NewRecorder()
+	respond(w, http.StatusOK, map[string]string{"key": "value"})
+	var result map[string]string
+	if err := json.NewDecoder(w.Body).Decode(&result); err != nil {
+		t.Fatalf("failed to decode response: %v", err)
+	}
+	if result["key"] != "value" {
+		t.Errorf("expected value, got %s", result["key"])
+	}
+}
+
+func TestRespondError_StatusCode(t *testing.T) {
+	w := httptest.NewRecorder()
+	respondError(w, http.StatusBadRequest, "invalid input")
+	if w.Code != http.StatusBadRequest {
+		t.Errorf("expected 400, got %d", w.Code)
+	}
+}
+
+func TestRespondError_Shape(t *testing.T) {
+	w := httptest.NewRecorder()
+	respondError(w, http.StatusBadRequest, "invalid input")
+	var result map[string]APIError
+	if err := json.NewDecoder(w.Body).Decode(&result); err != nil {
+		t.Fatalf("failed to decode error response: %v", err)
+	}
+	e, ok := result["error"]
+	if !ok {
+		t.Fatal("expected 'error' key in response")
+	}
+	if e.Code != "bad_request" {
+		t.Errorf("expected code bad_request, got %s", e.Code)
+	}
+	if e.Message != "invalid input" {
+		t.Errorf("expected message 'invalid input', got %s", e.Message)
+	}
+}
+
+func TestRespondError_CodeDerivation(t *testing.T) {
+	tests := []struct {
+		status int
+		want   string
+	}{
+		{http.StatusBadRequest, "bad_request"},
+		{http.StatusNotFound, "not_found"},
+		{http.StatusInternalServerError, "internal_server_error"},
+		{http.StatusUnauthorized, "unauthorized"},
+	}
+	for _, tt := range tests {
+		w := httptest.NewRecorder()
+		respondError(w, tt.status, "msg")
+		var result map[string]APIError
+		if err := json.NewDecoder(w.Body).Decode(&result); err != nil {
+			t.Fatalf("status %d: failed to decode: %v", tt.status, err)
+		}
+		if result["error"].Code != tt.want {
+			t.Errorf("status %d: expected code %s, got %s", tt.status, tt.want, result["error"].Code)
+		}
+	}
+}