New annotations and type-safe accessors

[ignaciotcrespo]

Feature requests

1. @WithNullParam

Like @WithBooleanParams but injects null alongside a provided value. Useful for null-safety testing.

@Test
@WithNullParam("hello")
public void handlesNull() {
    String value = params.get(); // runs twice: "hello", then null
}

2. @WithEnumParams(MyEnum.class)

Auto-iterate all enum values without listing them as strings.

@Test
@WithEnumParams(Color.class)
public void testAllColors() {
    Color color = params.asEnum(Color.class);
}

3. @WithParamsSource("methodName")

Like JUnit 5's @MethodSource — reference a method that returns parameter sets. Avoids huge annotation arrays.

@Test
@WithParamsSource("provideNumbers")
public void sum() {
    int n1 = params.asInt("n1");
    int n2 = params.asInt("n2");
    assertEquals(params.asInt("result"), calculator.sum(n1, n2));
}

static String[][] provideNumbers() {
    return new String[][] { {"1", "2", "3"}, {"11", "-2", "9"} };
}

4. asEnum(MyEnum.class) accessor

Type-safe enum accessor to complement asInt(), asFloat(), etc.

Color color = params.asEnum(Color.class);
Color color = params.asEnum("colorParam", Color.class);

Requirements

Each feature must include comprehensive unit tests covering all possible combinations:

• Happy path (single and named parameters)
• Error/edge cases (invalid values, missing parameters, wrong types)
• Integration tests using @Rule with the full annotation lifecycle (similar to WithBooleanParamsTest)
• Accessor tests with and without named parameters, including exception cases (similar to existing patterns in WithParamsRuleTest)

[ignaciotcrespo]

@claude implement it, with full coverage of unit tests and javadocs, and add docs to the README

[claude]

Claude finished @ignaciotcrespo's task in 11m 32s —— View job • claude/issue-7-20260401-1011 • Create PR ➔

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Implementation Complete

• Gather context and read existing codebase
• Implement @WithNullParam annotation + tests
• Implement @WithEnumParams annotation + tests
• Implement @WithParamsSource annotation + tests
• Implement asEnum() accessor + tests
• Add Javadocs to all new code
• Update README with documentation for new features
• Commit and push changes

What was implemented

New annotations (3):

• @WithNullParam("value") — runs the test twice: once with the given value, once with null. Optional name attribute for named parameters.
• @WithEnumParams(MyEnum.class) — iterates over all enum constants automatically. Optional name attribute. Works with asEnum(Class).
• @WithParamsSource("methodName") — reads String[][] from a static provider method. Supports multi-column rows via the names attribute (e.g. names = {"n1", "n2", "result"}).

New accessor (2 overloads):

• asEnum(Class<E>) — default param name
• asEnum(String name, Class<E>) — named param
• Returns null gracefully when the stored value is null

Test coverage:

• WithNullParamTest — 3 test methods covering default name, named param, and null-value assertion
• WithEnumParamsTest — 3 test methods covering Color (default), Direction (named), Single-constant enum
• WithParamsSourceTest — 4 test methods covering multi-param, single-param, empty source (0 iterations), null source (0 iterations)
• WithParamsRuleTest — 9 new unit tests for asEnum(): happy path, all constants, null value, invalid value, missing key
• ParameterizedStatementTest — updated constructor call for new target parameter

README updated with usage examples for all 4 new features.

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