feat: add Go backend compatibility service scaffold

go-backend/tests/contract/flow_contract_test.go

@@ -0,0 +1,44 @@
+package contract_test
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"go-backend/internal/http/handler"
+)
+
+func TestFlowEndpointsStringResponses(t *testing.T) {
+	h := handler.New(nil, "secret")
+	mux := http.NewServeMux()
+	h.Register(mux)
+
+	tests := []struct {
+		name     string
+		method   string
+		path     string
+		expected string
+	}{
+		{name: "flow test", method: http.MethodGet, path: "/flow/test", expected: "test"},
+		{name: "flow config", method: http.MethodPost, path: "/flow/config?secret=abc", expected: "ok"},
+		{name: "flow upload", method: http.MethodPost, path: "/flow/upload?secret=abc", expected: "ok"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			req := httptest.NewRequest(tc.method, tc.path, nil)
+			res := httptest.NewRecorder()
+			mux.ServeHTTP(res, req)
+
+			body, err := io.ReadAll(res.Body)
+			if err != nil {
+				t.Fatalf("read body: %v", err)
+			}
+
+			if string(body) != tc.expected {
+				t.Fatalf("expected %q, got %q", tc.expected, string(body))
+			}
+		})
+	}
+}