JUnit field injection

[prdoyle]

JUnit's parameterization is not composable. Any given class has to decide, once and for all, what all its argument sources are, and that means (for example) superclasses can't introduce their own parameters and argument sources.

This PR extends our existing injection extension so it can inject into fields annotated with @Injected.

[Copilot]

Pull request overview

This PR extends the bosk-junit injection mechanism to support class-level field injection (via @Injected fields and a new @InjectFields class template), enabling more composable test parameterization than JUnit’s @ParameterizedClass.

Changes:

• Introduces Injector (replacing ParameterInjector) with unified support for parameters and fields (AnnotatedElement-based).
• Adds field injection support (@Injected, @InjectFields, FieldInjectionContextProvider) and shared branching logic (ParameterInjectionSupport).
• Refactors multiple test suites (boson, mongo, sql, testing, core) to use @InjectFrom + field injection instead of JUnit @ParameterizedClass, and adds new injectors/docs.

Reviewed changes

Copilot reviewed 46 out of 46 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
boson/src/test/java/works/bosk/boson/types/DataTypeHasWildcardsTest.java	Migrates test injectors to the new Injector API.
boson/src/test/java/works/bosk/boson/codec/io/JsonSuiteTest.java	Replaces @ParameterizedClass usage with @InjectFrom.
boson/src/test/java/works/bosk/boson/codec/io/JsonReaderValidateSyntaxTest.java	Switches from constructor/class parameterization to field injection + standard @Test lifecycle.
boson/src/test/java/works/bosk/boson/codec/io/JsonReaderValidateSyntaxInjector.java	Adds dedicated injector supplying validate-syntax reader factories.
boson/src/test/java/works/bosk/boson/codec/io/JsonReaderInvalidTokenTest.java	Replaces @ParameterizedClass usage with @InjectFrom.
boson/src/test/java/works/bosk/boson/codec/io/JsonReaderInjector.java	Adds shared JsonReader supplier injector for reader-based test suites.
boson/src/test/java/works/bosk/boson/codec/io/JsonReaderHappyTest.java	Replaces @ParameterizedClass usage with @InjectFrom.
boson/src/test/java/works/bosk/boson/codec/io/AbstractJsonReaderTest.java	Converts class-level parameterization to injected field (Function<String, JsonReader>).
boson/src/test/java/works/bosk/boson/codec/SettingsInjector.java	Updates settings injector to Injector API.
boson/src/test/java/works/bosk/boson/codec/RoundTripTest.java	Migrates from constructor parameterization to @InjectFields + injected settings.
boson/src/test/java/works/bosk/boson/codec/PrimitiveTypeInjector.java	Updates primitive type injector to Injector API.
boson/src/test/java/works/bosk/boson/codec/PrimitiveInjector.java	Updates primitive-number injector to Injector API.
boson/src/test/java/works/bosk/boson/codec/CodecHappyParseTest.java	Converts settings from ctor parameter to injected field + @BeforeEach init.
boson/src/test/java/works/bosk/boson/codec/BasicCodecTest.java	Converts settings from ctor parameter to injected field + @BeforeEach init.
boson/build.gradle	Adds bosk-junit as a test dependency for boson tests.
bosk-testing/src/test/java/works/bosk/testing/drivers/ForgottenFlushTest.java	Updates initial-state method references to instance form.
bosk-testing/src/main/java/works/bosk/testing/drivers/SharedDriverConformanceTest.java	Updates initial-state method references to instance form.
bosk-testing/src/main/java/works/bosk/testing/drivers/DriverConformanceTest.java	Migrates internal injectors to Injector API and AnnotatedElement checks.
bosk-testing/src/main/java/works/bosk/testing/drivers/AbstractDriverTest.java	Makes initialState an instance method; adjusts logging to keep TestInfo in a field.
bosk-sql/src/test/java/works/bosk/drivers/sql/SqlDriverDurabilityTest.java	Replaces @ParameterizedClass with field injection for database selection.
bosk-sql/src/test/java/works/bosk/drivers/sql/DatabaseInjector.java	Adds database injector for SQL driver tests.
bosk-mongo/src/test/java/works/bosk/drivers/mongo/internal/To.java	Adds field marker annotation to disambiguate injected configs.
bosk-mongo/src/test/java/works/bosk/drivers/mongo/internal/SchemaEvolutionTest.java	Replaces class parameterization with field injection + marker annotations for cartesian config pairs.
bosk-mongo/src/test/java/works/bosk/drivers/mongo/internal/MongoDriverHanoiTest.java	Replaces @ParameterizedClass with field injection and @BeforeEach setup.
bosk-mongo/src/test/java/works/bosk/drivers/mongo/internal/From.java	Adds field marker annotation to disambiguate injected configs.
bosk-mongo/src/test/java/works/bosk/drivers/mongo/internal/DottedFieldNameTest.java	Extends AbstractDriverTest and migrates initial-state method reference usage.
bosk-mongo/build.gradle	Adds bosk-junit as a test dependency for mongo tests.
bosk-junit/src/test/java/works/bosk/junit/ParameterizedClassTest.java	Removes old tests tied to @ParameterizedClass/ParameterInjector.
bosk-junit/src/test/java/works/bosk/junit/ParameterInjectionContextProviderTest.java	Removes old tests for the prior parameter injection implementation.
bosk-junit/src/test/java/works/bosk/junit/CorrelatedParameterTest.java	Removes manual/disabled correlated injection test for old API.
bosk-junit/src/test/java/works/bosk/junit/InjectFromHappyPathTests.java	Adds new happy-path tests for field and method injection behavior under JUnit.
bosk-junit/src/main/java/works/bosk/junit/ParameterInjectionSupport.java	Introduces shared branch/cartesian-product/injector instantiation logic used by both injection modes.
bosk-junit/src/main/java/works/bosk/junit/ParameterInjectionContextProvider.java	Refactors to use shared support and incorporate class-level branch state.
bosk-junit/src/main/java/works/bosk/junit/Injector.java	Renames/expands injector interface to support both fields and parameters.
bosk-junit/src/main/java/works/bosk/junit/InjectedTest.java	Updates documentation to reflect Injector + field injection options.
bosk-junit/src/main/java/works/bosk/junit/Injected.java	Adds new annotation for field injection.
bosk-junit/src/main/java/works/bosk/junit/InjectFrom.java	Updates annotation to reference Injector and include fields in scope.
bosk-junit/src/main/java/works/bosk/junit/InjectFields.java	Adds new class-level annotation enabling field injection via @ClassTemplate.
bosk-junit/src/main/java/works/bosk/junit/FieldInjectionContextProvider.java	Adds new class template provider that instantiates test classes and populates injected fields.
bosk-junit/src/main/java/module-info.java	Adds SLF4J module requirement for new logging.
bosk-junit/USERS.md	Adds a user guide for injection features and usage patterns.
bosk-core/src/test/java/works/bosk/drivers/ReplicaSetTest.java	Updates initial-state method references to instance form.
bosk-core/src/test/java/works/bosk/drivers/ReplicaSetConformanceTest.java	Updates initial-state method references to instance form.
bosk-core/src/test/java/works/bosk/BoskContextTest.java	Updates initial-state method references to instance form.
bosk-core/src/test/java/works/bosk/IdentifierTest.java	Migrates injectors to Injector API and AnnotatedElement checks.
CLAUDE.md	Adds commit hygiene guidelines to contributor guidance.

Comments suppressed due to low confidence (1)

bosk-junit/src/main/java/works/bosk/junit/Injector.java:44

• Injector.ofType will never match anything: it compares element (a Parameter/Field) to type (a Class). This makes the helper unusable and silently breaks injection when callers use Injector.ofType. Compare elementType (or ((Parameter)element).getType()) to type instead.

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