feat: validate presence of optional @requires dependencies

execution/engine/execution_engine_helpers_test.go

@@ -44,14 +44,54 @@ func createTestRoundTripper(t *testing.T, testCase roundTripperTestCase) testRou
 				receivedBodyBytes, err = io.ReadAll(req.Body)
 				require.NoError(t, err)
 			}
-			require.Equal(t, testCase.expectedBody, string(receivedBodyBytes), "roundTripperTestCase body do not match")
+			require.Equal(t, testCase.expectedBody, string(receivedBodyBytes), "roundTripperTestCase received unexpected body")
 		}
 
 		body := bytes.NewBuffer([]byte(testCase.sendResponseBody))
 		return &http.Response{StatusCode: testCase.sendStatusCode, Body: io.NopCloser(body)}
 	}
 }
 
+type conditionalTestCase struct {
+	expectedHost   string
+	expectedPath   string
+	expectedMethod string
+
+	// responses map an expected body to the output that should be sent
+	responses map[string]sendResponse
+}
+
+type sendResponse struct {
+	statusCode int
+	body       string
+}
+
+func createConditionalTestRoundTripper(t *testing.T, testCase conditionalTestCase) testRoundTripper {
+	t.Helper()
+
+	require.True(t, len(testCase.responses) > 0, "no responses defined")
+
+	return func(req *http.Request) *http.Response {
+		t.Helper()
+
+		assert.Equal(t, testCase.expectedHost, req.URL.Host)
+		assert.Equal(t, testCase.expectedPath, req.URL.Path)
+
+		require.NotNil(t, req.Body, "roundTripperTestCase received nil body")
+
+		gotBody, err := io.ReadAll(req.Body)
+		require.NoError(t, err)
+		defer req.Body.Close()
+
+		require.Containsf(t, testCase.responses, string(gotBody), "received unexpected body: %v", string(gotBody))
+		response := testCase.responses[string(gotBody)]
+		return &http.Response{
+			StatusCode: response.statusCode,
+			Body:       io.NopCloser(bytes.NewBuffer([]byte(response.body))),
+		}
+	}
+}
+
 func stringify(any interface{}) []byte {
 	out, _ := json.Marshal(any)
 	return out