• Fixes JUnitAssertThrowsToAssertExceptionType does not convert cases where executable is a variable #511

Problem

JUnitAssertThrowsToAssertExceptionType was already rewriting assertThrows(..., executable) into assertThatExceptionOfType(...).isThrownBy(executable) even when executable is a variable, but the result did not compile: the variable stayed typed as JUnit's org.junit.jupiter.api.function.Executable, while AssertJ's isThrownBy requires ThrowableAssert.ThrowingCallable. These are distinct functional interfaces — a lambda/method reference coerces to either, a typed variable does not.

Change

When the executable argument is a variable typed exactly as Executable, the recipe now also retypes its declaration (and references) to ThrowingCallable, adding/removing imports accordingly.

This is guarded: the conversion only proceeds when every usage of that variable is an assertThrows executable argument (or the variable's own declaration/assignment). If the same variable is also passed somewhere that requires an Executable (e.g. assertAll), the types can't both be satisfied, so the call is left untouched rather than emitting non-compiling code.

Tests

• variableExecutable — local variable (the issue's core case)
• variableExecutableWithMessage — 3-arg form with .as(...)
• fieldExecutable — field declaration
• doNotRetypeExecutableSharedWithOtherJUnitAssertion — guard: variable shared with assertAll is left unchanged