new-test

Prompt file imported from jerarn/jaql (.github/prompts/new-test.prompt.md). Fill in {{headerPath}} before use. Copyright stays with the author.

Generate a unit test file for the public header {{headerPath}} (e.g. include/jaql/core/strong_type.hpp).

The test file lives at the mirrored path under tests/unit/: include/jaql/<module>/<header>.hpp → tests/unit/<module>/test_<header>.cpp

Read the target header now to understand the types, functions, and failure modes before generating any tests.

Also consult docs/testing-strategy.md for the full testing strategy.

Structure to follow

#include "jaql/<module>/<header>.hpp"

#include <gtest/gtest.h>
#include <gmock/gmock.h>

namespace jaql::<module>::test {

// --- Fixture (only if multiple tests share state) ---
class <ClassName>Test : public ::testing::Test {
protected:
    // shared setup
};

// --- Success paths ---
TEST_F(<ClassName>Test, <Method>_<Scenario>_<ExpectedOutcome>) {
    // Arrange
    // Act
    // Assert
}

// --- Error paths (one test per Result<T> failure mode) ---
TEST_F(<ClassName>Test, <Method>_<ErrorScenario>_ReturnsError) {
    auto result = /* call that should fail */;
    ASSERT_FALSE(result.has_value());
    EXPECT_EQ(result.error().code(), Code::<ExpectedCode>);
}

// --- Compile-time invariants ---
// Use static_assert to document and enforce type constraints.
static_assert(!std::is_convertible_v<double, MyStrongType>,
    "<MyStrongType> must not be implicitly constructible from double");

} // namespace jaql::<module>::test

Rules

1. One test per logical behaviour, not one test per function.
2. Naming: TEST(ClassName, MethodName_Scenario_ExpectedOutcome) — three underscore-separated parts.
3. Every Result<T> function must have at least one explicit error-path test.
4. Never use EXPECT_EQ or == to compare double. Use:
   • EXPECT_NEAR(actual, expected, abs_tolerance) for known absolute precision.
   • JAQL_EXPECT_NEAR_REL(actual, expected, rel_tolerance) for scale-varying results.
5. Use static_assert to verify compile-time type constraints (implicit conversion, move semantics, triviality, etc.).
6. Use ASSERT_TRUE(result.has_value()) << result.error().message(); before dereferencing a Result<T> in a test — a failing ASSERT stops the test and prints the error.
7. No using namespace at file scope. Use the full jaql::<module>:: prefix or a local using inside the test body.

Checklist before finishing

• File placed at tests/unit/<module>/test_<header>.cpp.
• All public functions have at least one success-path test.
• All Result<T> error codes are covered by at least one test.
• No bare == comparisons on floating-point values.
• static_assert used to document compile-time invariants where applicable.
• Corresponding CMakeLists.txt updated to add the new test_<header>.cpp source (or a new add_executable if this is the first test in the module).