Inconvertible Mockito `when` situation involving lambda and static method. by steve-aom-elliott · Pull Request #763 · openrewrite/rewrite-testing-frameworks

steve-aom-elliott · 2025-07-09T19:53:04Z

Showing situation where we wouldn't be able to safely convert when(..).thenReturn(..) to staticMocked.when(..).thenReturn(..)

Overview

There's a situation that looks something like this:

import org.mockito.MockedConstruction;

import static org.mockito.Mockito.*;

class A {
    public static Integer returnPassedIn(Integer number) {
        return number;
    }
}

class Test {
    void method() {
        try (MockedConstruction<A> aMockConstruction = mockConstruction(A.class,
            (mock, context) -> {
                when(mock.returnPassedIn(any(Integer.class))).thenReturn(42);
            }
        )) {
            // other stuff that doesn't call on `aMockConstruction` directly
        }
    }
}

The current behaviour is that it ends up becoming:

import org.mockito.MockedConstruction;
import org.mockito.MockedStatic;

import static org.mockito.Mockito.*;

class A {
    public static Integer returnPassedIn(Integer number) {
        return number;
    }
}

class Test {
    void method() {
        try (MockedConstruction<A> aMockConstruction = mockConstruction(A.class,
                (mock, context) -> {
                    try (MockedStatic<mock> mockmock1 = mockStatic(mock.class)) {
                        mockmock1.when(() -> mock.returnPassedIn(any(Integer.class))).thenReturn(42);
                    }
                }
        )) {
            // other stuff that doesn't call on `aMockConstruction` directly
        }
    }
}

Which won't compile due to trying to it trying to use mock as a class both in the typing of MockedStatic<mock> and in the parameter of mockStatic(mock.class).

While it might be possible to change it do something like (by reaching the type of the parameter rather than the parameter itself):

import org.mockito.MockedConstruction;
import org.mockito.MockedStatic;

import static org.mockito.Mockito.*;

class A {
    public static Integer returnPassedIn(Integer number) {
        return number;
    }
}

class Test {
    void method() {
        try (MockedConstruction<A> aMockConstruction = mockConstruction(A.class,
                (mock, context) -> {
                    try (MockedStatic<A> mockmock1 = mockStatic(A.class)) {
                        mockmock1.when(() -> A.returnPassedIn(any(Integer.class))).thenReturn(42);
                    }
                }
        )) {
            // other stuff that doesn't call on `aMockConstruction` directly
        }
    }
}

I'd argue that this looks more confusing and doesn't actually persist the same scoping of the method being mocked.

Ideally it would have changed to:

import org.mockito.MockedConstruction;
import org.mockito.MockedStatic;

import static org.mockito.Mockito.*;

class A {
    public static Integer returnPassedIn(Integer number) {
        return number;
    }
}

class Test {
    void method() {
        try (MockedStatic<A> aMock = mockStatic(A.class)) {
                aMock.when(() -> A.returnPassedIn(any(Integer.class))).thenReturn(42);
                // other stuff from the original
        }
    }
}

But I'm not sure how complicated said change would be to get correct in all cases.

What's changed?

There's a particular setup that would require a wider scoped change than the current recipe is trying to target to get correct, and would require context about how a try-with-resource variable is used to get correct. Current thought is that rather than have it result immediately in something that can't be compiled, to not make a change instead.

Checklist

I've added unit tests to cover both positive and negative cases
I've read and applied the recipe conventions and best practices
I've used the IntelliJ IDEA auto-formatter on affected files

github-actions

Some suggestions could not be made:

src/test/java/org/openrewrite/java/testing/mockito/MockitoWhenOnStaticToMockStaticTest.java
- lines 57-95
- lines 136-135

…..).thenReturn(..)` to `staticMocked.when(...).thenReturn(..)`

…meter as a class, which leads to something that can't be compiled.

…OnStaticToMockStatic.java

…rom 3.11.0 to 3.15.0 [skip ci] Bumps [org.openrewrite.recipe:rewrite-testing-frameworks](https://github.com/openrewrite/rewrite-testing-frameworks) from 3.11.0 to 3.15.0. Release notes *Sourced from [org.openrewrite.recipe:rewrite-testing-frameworks's releases](https://github.com/openrewrite/rewrite-testing-frameworks/releases).* > 3.15.0 > ------ > > What's Changed > -------------- > > * Include additional AssertJ migrations by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#773](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/773) > * Include recipes in larger composites where possible by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#774](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/774) > * Retain comments when chaining assertions by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#775](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/775) > * refactor: Static imports for Collections and Collectors by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#779](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/779) > * Added implementation to extract any expression arguments from last statement in assertThrows by [`@JohannisK`](https://github.com/JohannisK) in [openrewrite/rewrite-testing-frameworks#724](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/724) > * Don't clean up mockito imports for Kotlin by [`@jevanlingen`](https://github.com/jevanlingen) in [openrewrite/rewrite-testing-frameworks#782](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/782) > * Adding dependency guards to the Junit 4 -> 5 migration for when the POM or build.gradle have a dependency on `org.testng:testng`. by [`@steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-testing-frameworks#760](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/760) > * rename settings.local.json to settings.json by [`@zieka`](https://github.com/zieka) in [openrewrite/rewrite-testing-frameworks#783](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/783) > * Fix ClassCastException in PowerMockitoWhenNewToMockito by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#786](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/786) > * MockitoJUnitRunnerToExtension: Handle existing MockitoExtension by [`@amishra-u`](https://github.com/amishra-u) in [openrewrite/rewrite-testing-frameworks#788](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/788) > > **Full Changelog**: <openrewrite/rewrite-testing-frameworks@v3.14.0...v3.15.0> > > 3.14.1 > ------ > > What's Changed > -------------- > > * OpenRewrite v8.59.1: <https://github.com/openrewrite/rewrite> > > **Full Changelog**: <https://github.com/openrewrite/rewrite-testing-frameworks> > > 3.14.0 > ------ > > What's Changed > -------------- > > * Collapse more consecutive assertions by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#769](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/769) > * refactor: Unwrap else block after return or throw statement by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-testing-frameworks#771](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/771) > * Remove all PowerMock imports after migration by [`@JohannisK`](https://github.com/JohannisK) in [openrewrite/rewrite-testing-frameworks#770](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/770) > * Remove `assertTrue(true)` and `assertFalse(false)` by [`@aet2505`](https://github.com/aet2505) in [openrewrite/rewrite-testing-frameworks#767](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/767) > > New Contributors > ---------------- > > * [`@aet2505`](https://github.com/aet2505) made their first contribution in [openrewrite/rewrite-testing-frameworks#767](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/767) > > **Full Changelog**: <openrewrite/rewrite-testing-frameworks@v3.13.0...v3.14.0> > > 3.13.0 > ------ > > What's Changed > -------------- > > * Removing `NoInitializationForInjectMock` recipe due to side effects when using recipe by [`@steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-testing-frameworks#765](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/765) > * Adding functionality to `MockitoWhenOnStaticToMockStatic` for recognizing an existing try-with-resources `MockedStatic<T>` can be reused instead of creating a new one. by [`@steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-testing-frameworks#766](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/766) > * Inconvertible Mockito `when` situation involving lambda and static method. by [`@steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-testing-frameworks#763](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/763) > * Changing order of `mockito-all` -> `mockito-core` change vs `org.mockito:*` upgrade, and made the former upgrade to `3.x` at the same time, as there aren't aligned versions between the two. by [`@steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-testing-frameworks#768](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/768) > > New Contributors > ---------------- > > * [`@steve-aom-elliott`](https://github.com/steve-aom-elliott) made their first contribution in [openrewrite/rewrite-testing-frameworks#765](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/765) > > **Full Changelog**: <openrewrite/rewrite-testing-frameworks@v3.12.0...v3.13.0> > > 3.12.0 > ------ > > What's Changed > -------------- > > * Fix for JUnit test method throws clause preservation by [`@knutwannheden`](https://github.com/knutwannheden) in [openrewrite/rewrite-testing-frameworks#755](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/755) > * refactor: org.openrewrite.mavencentral by [`@Laurens-W`](https://github.com/Laurens-W) in [openrewrite/rewrite-testing-frameworks#756](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/pull/756) ... (truncated) Commits * [`76c6888`](openrewrite/rewrite-testing-frameworks@76c6888) MockitoJUnitRunnerToExtension: Handle existing MockitoExtension ([#788](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/issues/788)) * [`75d2019`](openrewrite/rewrite-testing-frameworks@75d2019) Retain `Throwable` in `SimplifyTestThrows` * [`0ea47e9`](openrewrite/rewrite-testing-frameworks@0ea47e9) Include `SimplifyTestThrows` with `JUnit5BestPractices` * [`efb0a4e`](openrewrite/rewrite-testing-frameworks@efb0a4e) Add AssertJ change type recipes for classes deprecated in v3.27.4 * [`f203a20`](openrewrite/rewrite-testing-frameworks@f203a20) Update documentation examples * [`69d7716`](openrewrite/rewrite-testing-frameworks@69d7716) Fix ClassCastException in PowerMockitoWhenNewToMockito ([#786](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/issues/786)) * [`dc6f272`](openrewrite/rewrite-testing-frameworks@dc6f272) rename settings.local.json to settings.json ([#783](https://redirect.github.com/openrewrite/rewrite-testing-frameworks/issues/783)) * [`96fca52`](openrewrite/rewrite-testing-frameworks@96fca52) Documentation example for MockitoJUnitRunnerToExtensionTest * [`9a2082a`](openrewrite/rewrite-testing-frameworks@9a2082a) Adding dependency guards to the Junit 4 -> 5 migration for when the POM or bu... * [`74366cf`](openrewrite/rewrite-testing-frameworks@74366cf) OpenRewrite recipe best practices * Additional commits viewable in [compare view](openrewrite/rewrite-testing-frameworks@v3.11.0...v3.15.0) [![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility\_score?dependency-name=org.openrewrite.recipe:rewrite-testing-frameworks&package-manager=maven&previous-version=3.11.0&new-version=3.15.0)](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores) Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`. [//]: # (dependabot-automerge-start) [//]: # (dependabot-automerge-end) --- Dependabot commands and options You can trigger Dependabot actions by commenting on this PR: - `@dependabot rebase` will rebase this PR - `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it - `@dependabot merge` will merge this PR after your CI passes on it - `@dependabot squash and merge` will squash and merge this PR after your CI passes on it - `@dependabot cancel merge` will cancel a previously requested merge and block automerging - `@dependabot reopen` will reopen this PR if it is closed - `@dependabot close` will close this PR and stop Dependabot recreating it. 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steve-aom-elliott self-assigned this Jul 9, 2025

steve-aom-elliott added the bug Something isn't working label Jul 9, 2025

steve-aom-elliott added this to OpenRewrite Jul 9, 2025

steve-aom-elliott added the mockito label Jul 9, 2025

github-project-automation Bot moved this to In Progress in OpenRewrite Jul 9, 2025

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steve-aom-elliott force-pushed the mock-static-cannot-safely-convert branch from 9ad8261 to 48b949f Compare July 9, 2025 19:57

steve-aom-elliott added 2 commits July 11, 2025 16:56

Showing situation where we wouldn't be able to safely convert `when(.…

b4958a3

…..).thenReturn(..)` to `staticMocked.when(...).thenReturn(..)`

Adding a change that would prevent it from tring to use a lambda para…

80cb9c3

…meter as a class, which leads to something that can't be compiled.

steve-aom-elliott force-pushed the mock-static-cannot-safely-convert branch from 48b949f to 80cb9c3 Compare July 11, 2025 20:57

steve-aom-elliott moved this from In Progress to Ready to Review in OpenRewrite Jul 11, 2025

steve-aom-elliott marked this pull request as ready for review July 11, 2025 21:03

sambsnyd reviewed Jul 11, 2025

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Comment thread src/main/java/org/openrewrite/java/testing/mockito/MockitoWhenOnStaticToMockStatic.java Outdated

Update src/main/java/org/openrewrite/java/testing/mockito/MockitoWhen…

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…OnStaticToMockStatic.java

sambsnyd merged commit 5dd6582 into main Jul 11, 2025
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Inconvertible Mockito `when` situation involving lambda and static method.#763

Inconvertible Mockito `when` situation involving lambda and static method.#763
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steve-aom-elliott commented Jul 9, 2025 •

edited

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steve-aom-elliott commented Jul 9, 2025 •

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