Write tests with proper assertions to ensure reliability and maintainability. Follow these guidelines: 1. **Check for empty data** before proceeding with tests to prevent invalid test conditions: ```cpp string path = cvtest::findDataFile("test_image.png"); Mat img = imread(path); ASSERT_FALSE(img.empty()) << "Cannot open test image: " << path; ``` 2. **Use ASSERT_* for critical conditions** that should halt test execution when failed: ```cpp // Use ASSERT_TRUE for file operations and resource initialization ASSERT_TRUE(fs.isOpened()) << "Failed to open file"; // Use EXPECT_* for test validations that shouldn't interrupt the test EXPECT_EQ(dst.cols, 270); ``` 3. **Maintain correct parameter order** in equality assertions with (expected, actual) to generate meaningful error messages: ```cpp // Correct: ASSERT_EQ(expected_reference, actual_result) ASSERT_EQ(4, img.channels()); EXPECT_EQ(6, lines[0][0]); ``` 4. **Use specialized assertions** for common comparisons instead of custom loops: ```cpp // Use instead of manual matrix comparison loops EXPECT_MAT_NEAR(src_mat, dst_mat, 0); // or EXPECT_PRED_FORMAT2(cvtest::MatComparator(0, 0), src_mat, dst_mat); ``` Well-written assertions make tests more reliable, easier to debug, and help identify the exact cause of failures.