Implement Phase 4 test coverage

internal/httputil/json_test.go

@@ -0,0 +1,85 @@
+package httputil
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestDecodeJSONStrict(t *testing.T) {
+	t.Run("valid", func(t *testing.T) {
+		var got struct {
+			Name string `json:"name"`
+		}
+		req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(`{"name":"demo"}`))
+		rr := httptest.NewRecorder()
+		if !DecodeJSON(rr, req, &got) {
+			t.Fatalf("DecodeJSON returned false: %s", rr.Body.String())
+		}
+		if got.Name != "demo" {
+			t.Fatalf("unexpected decoded value: %#v", got)
+		}
+	})
+
+	t.Run("unknown field", func(t *testing.T) {
+		var got struct {
+			Name string `json:"name"`
+		}
+		req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(`{"name":"demo","extra":true}`))
+		rr := httptest.NewRecorder()
+		if DecodeJSON(rr, req, &got) {
+			t.Fatal("DecodeJSON returned true for unknown field")
+		}
+		if rr.Code != http.StatusBadRequest {
+			t.Fatalf("status = %d, want %d", rr.Code, http.StatusBadRequest)
+		}
+		if !strings.Contains(rr.Body.String(), "unknown field") {
+			t.Fatalf("unexpected body: %s", rr.Body.String())
+		}
+	})
+
+	t.Run("invalid json", func(t *testing.T) {
+		var got map[string]string
+		req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(`{`))
+		rr := httptest.NewRecorder()
+		if DecodeJSON(rr, req, &got) {
+			t.Fatal("DecodeJSON returned true for invalid JSON")
+		}
+		if rr.Code != http.StatusBadRequest {
+			t.Fatalf("status = %d, want %d", rr.Code, http.StatusBadRequest)
+		}
+	})
+}
+
+func TestWriteJSONAndError(t *testing.T) {
+	rr := httptest.NewRecorder()
+	WriteJSON(rr, http.StatusCreated, map[string]string{"status": "ok"})
+	if rr.Code != http.StatusCreated {
+		t.Fatalf("status = %d", rr.Code)
+	}
+	if ct := rr.Header().Get("Content-Type"); ct != "application/json" {
+		t.Fatalf("content-type = %q", ct)
+	}
+	var body map[string]string
+	if err := json.Unmarshal(rr.Body.Bytes(), &body); err != nil {
+		t.Fatal(err)
+	}
+	if body["status"] != "ok" {
+		t.Fatalf("unexpected body: %#v", body)
+	}
+
+	rr = httptest.NewRecorder()
+	WriteError(rr, http.StatusTeapot, "short and stout")
+	if rr.Code != http.StatusTeapot {
+		t.Fatalf("status = %d", rr.Code)
+	}
+	body = map[string]string{}
+	if err := json.Unmarshal(rr.Body.Bytes(), &body); err != nil {
+		t.Fatal(err)
+	}
+	if body["error"] != "short and stout" {
+		t.Fatalf("unexpected error body: %#v", body)
+	}
+}