EasyMock to Mockito

[jpraet]

What problem are you trying to solve?

Migrate from EasyMock to Mockito.

Resources:

• https://wiki.magnolia-cms.com/display/DEV/Converting+Easymock-Tests+to+Mockito
• https://gist.github.com/stefanbirkner/1095194/904909cc229b6acb55c18f529e396089129e20e9

[timtebeek]

Hi @jpraet ! Thanks for the suggestion; looking at the gist link this appears relatively straightforward:

  sed -i 's/org.easymock.EasyMock.createNiceMock/org.mockito.Mockito.mock/g' $item
  sed -i 's/org.easymock.EasyMock.createMock/org.mockito.Mockito.mock/g' $item
  sed -i 's/org.easymock.EasyMock.expect/org.mockito.Mockito.when/g' $item
  sed -i 's/org.easymock.EasyMock/org.mockito.Mockito/g' $item
  sed -i 's/EasyMock/Mockito/g' $item
  sed -i 's/createNiceMock/mock/g' $item
  sed -i 's/createMock/mock/g' $item
  sed -i 's/expect(/when(/g' $item
  sed -i 's/andReturn/thenReturn/g' $item
  sed -i 's/\.anyTimes()//g' $item
  sed -i '/replay[^A-Za-z0-9]/d' $item

At first glance most, if not all of these can be converted to use recipes we already have which you can compose in our recipe builder at https://app.moderne.io/recipes/builder
For instance the first conversion could be replaced by

type: specs.openrewrite.org/v1beta/recipe
name: java.testing.easymock.EasyMockToMockito
displayName: Migrate from EasyMock to Mockito
description: This recipe will apply changes commonly needed when migrating from EasyMock to Mockito.
recipeList:
  - org.openrewrite.java.ChangeMethodTargetToStatic:
      methodPattern: org.easymock.EasyMock createNiceMock(..)
      fullyQualifiedTargetTypeName: org.mockito.Mockito
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.mockito.Mockito createNiceMock(..)
      newMethodName: mock
...

We already have a very similar recipe for JMockit: https://github.com/openrewrite/rewrite-testing-frameworks/blob/main/src/main/resources/META-INF/rewrite/jmockit.yml

Would you be willing to create a first draft of these migration recipes to get this started?

[dblackhall-tyro]

type: specs.openrewrite.org/v1beta/recipe
name: org.openrewrite.java.testing.easymock.EasyMockToMockito
displayName: Migrate from EasyMock to Mockito
description: This recipe will apply changes commonly needed when migrating from EasyMock to Mockito.
tags:
  - testing
  - easymock
recipeList:
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.IExpectationSetters times(..)
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.IExpectationSetters once()
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.IExpectationSetters atLeastOnce()
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.IExpectationSetters anyTimes()
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.easymock.IExpectationSetters andReturn(..)
      newMethodName: thenReturn
      ignoreDefinition: true
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.easymock.IExpectationSetters andThrow(java.lang.Throwable)
      newMethodName: thenThrow
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.easymock.IExpectationSetters andAnswer(..)
      newMethodName: thenAnswer
      ignoreDefinition: true
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.easymock.IExpectationSetters andStubReturn(..)
      newMethodName: thenReturn
      ignoreDefinition: true
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.easymock.IExpectationSetters andStubThrow(java.lang.Throwable)
      newMethodName: thenThrow
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.easymock.IExpectationSetters andStubAnswer(..)
      newMethodName: thenAnswer
      ignoreDefinition: true
  - org.openrewrite.java.ChangeMethodTargetToStatic:
      methodPattern: org.easymock.IMocksControl mock(..)
      fullyQualifiedTargetTypeName: org.mockito.Mockito
  - org.openrewrite.java.ChangeMethodTargetToStatic:
      methodPattern: org.easymock.IMocksControl createMock(..)
      fullyQualifiedTargetTypeName: org.mockito.Mockito
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.IMocksControl replay(..)
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.IMocksControl verify(..)
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.IMocksControl verifyRecording(..)
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.IMocksControl verifyUnexpectedCalls(..)
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.EasyMockSupport replayAll()
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.easymock.EasyMockSupport verifyAll()
#  - com.todo.openrewrite.java.easymock.RemoveExtendsEasyMockSupport
  - org.openrewrite.java.ChangeType:
      oldFullyQualifiedTypeName: org.easymock.EasyMock
      newFullyQualifiedTypeName: org.mockito.Mockito
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.mockito.Mockito createNiceMock(..)
      newMethodName: mock
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.mockito.Mockito createStrictMock(..)
      newMethodName: mock
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.mockito.Mockito createMock(..)
      newMethodName: mock
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.mockito.Mockito niceMock(..)
      newMethodName: mock
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.mockito.Mockito strictMock(..)
      newMethodName: mock
  - org.openrewrite.java.ReorderMethodArguments:
      methodPattern: org.mockito.Mockito mock(String, Class)
      newParameterNames:
        - classToMock
        - name
      oldParameterNames:
        - name
        - classToMock
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.mockito.Mockito reportMatcher(..)
      newMethodName: argThat
  - org.openrewrite.java.ChangeMethodName:
      methodPattern: org.mockito.Mockito expect(..)
      newMethodName: when
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.mockito.Mockito replay(..)
  - org.openrewrite.java.migrate.RemoveMethodInvocation:
      methodPattern: org.mockito.Mockito verify(..)
#  - com.todo.openrewrite.java.easymock.RefactorEasyMockIArgumentMatcherIntoMockitoArgumentMatcher
#  - com.todo.openrewrite.java.easymock.RewriteEasyMockExpectationsIntoMockitoVerify
  - org.openrewrite.java.dependencies.AddDependency:
      groupId: org.mockito
      artifactId: mockito-core
      version: 5.x
      onlyIfUsing: org.mockito.*
  - org.openrewrite.java.dependencies.RemoveDependency:
      groupId: org.easymock
      artifactId: easymock

There are some more complicated behaviours I have found in my codebase that will require some more complicated recipes e.g:

• expectLastCall()
• test classes that extend EasyMockSupport

But for a first draft, it does quite well :)

[dblackhall-tyro]

RemoveExtendsEasyMockSupport was easy enough (I just copied the bits I needed from MigrateJUnitTestCase)

public class RemoveExtendsEasyMockSupport extends Recipe {

    @Override
    public @NlsRewrite.DisplayName String getDisplayName() {
        return "Migrate Test classes that extend `org.easymock.EasyMockSupport` to use Mockito";
    }

    @Override
    public @NlsRewrite.Description String getDescription() {
        return "Modify test classes by removing extends EasyMockSupport and replacing EasyMock methods with Mockito equivalents.";
    }

    private static boolean isSupertypeTestCase(JavaType.@Nullable FullyQualified fullyQualified) {
        if (fullyQualified == null || fullyQualified.getSupertype() == null || "java.lang.Object".equals(fullyQualified.getFullyQualifiedName())) {
            return false;
        }

        JavaType.FullyQualified fqType = TypeUtils.asFullyQualified(fullyQualified);
        if (fqType != null && "org.easymock.EasyMockSupport".equals(fqType.getFullyQualifiedName())) {
            return true;
        }
        return isSupertypeTestCase(fullyQualified.getSupertype());
    }

    @Override
    public TreeVisitor<?, ExecutionContext> getVisitor() {
        return new EasyMockSupportVisitor();
    }

    private static class EasyMockSupportVisitor extends JavaIsoVisitor<ExecutionContext> {
        @Override
        public J.ClassDeclaration visitClassDeclaration(J.ClassDeclaration classDecl, ExecutionContext ctx) {
            if (!isSupertypeTestCase(classDecl.getType())) {
                return classDecl;
            }
            J.ClassDeclaration cd = super.visitClassDeclaration(classDecl, ctx);
            if (cd.getExtends() != null && cd.getExtends().getType() != null) {
                JavaType.FullyQualified fullQualifiedExtension = TypeUtils.asFullyQualified(cd.getExtends().getType());
                if (fullQualifiedExtension != null && "org.easymock.EasyMockSupport".equals(fullQualifiedExtension.getFullyQualifiedName())) {
                    cd = cd.withExtends(null);
                }
            }
            maybeRemoveImport("org.easymock.EasyMockSupport");
            return cd;
        }
    }
}

class RemoveExtendsEasyMockSupportTest implements RewriteTest {

    @Override
    public void defaults(RecipeSpec spec) {
        spec.recipe(new RemoveExtendsEasyMockSupport());
    }

    @Test
    public void shouldRemoveEasyMockSupportParentClass() {
        rewriteRun(
          //language=java
            java(
                """
                package com.todo.openrewrite.easymock;
                
                import org.easymock.EasyMockSupport;
    
                public class MigrateEasyMockSupportTest extends EasyMockSupport {
                }
                """,
                """
                package com.tyro.openrewrite.easymock;
    
                public class MigrateEasyMockSupportTest {
                }
                """
            )
        );
    }

    @Test
    public void shouldLeaveClassesWithoutEasyMockSupportAlone() {
        rewriteRun(
          //language=java
            java(
                """
                package com.todo.openrewrite.easymock;
                
                public class MigrateEasyMockSupportTest {
                }
                """
            )
        );
    }

    @Test
    public void shouldLeaveClassesWithDifferentExtendsAlone() {
        rewriteRun(
          //language=java
          java(
            """
            package com.todo.openrewrite.easymock;
            
            import javax.management.monitor.Monitor;
            
            public class MigrateEasyMockSupportTest extends Monitor {
            }
            """
          )
        );
    }
}

[timtebeek]

Thanks a lot for sharing @dblackhall-tyro ! Great to see this kicked off. Would you be willing to contribute these on a draft PR? That way you get credited as the recipe author in our docs. We can collaborate and iterate from there.

[dblackhall-tyro]

Certainly! I've found a few more small cases over the last few days so I'll wrap them all up and create a PR