Just like stubbing, Argument matchers can be used for verification also.

Example

Example Application

package com.logicbig.example;

public interface MyService {
  public int doSomething(String processName);
}

package com.logicbig.example;

public class MyProcessor {
  private String processName;
  private MyService myService;

  public MyProcessor(String processName, MyService myService) {
      this.processName = processName;
      this.myService = myService;
  }

  public void process() {
      int returnInteger = processName != null ? myService.doSomething(processName) : -1;
      System.out.println("My Integer is: " + returnInteger);
  }
}

Using argument matcher with verify()

Following example uses Mockito.anyString() argument matcher with verify() method:

package com.logicbig.example;

import org.junit.Test;
import org.mockito.Mockito;

public class ProcessorTest {

  @Test
  public void processTest() {
      MyService myService = Mockito.mock(MyService.class);
      String processName = "dummy-process-name";
      Mockito.when(myService.doSomething(processName))
             .thenReturn(10);
      MyProcessor myProcessor = new MyProcessor(processName, myService);
      myProcessor.process();
      Mockito.verify(myService).doSomething(Mockito.anyString());
  }
}

D:\mockito-verify-method-with-argument-matchers-example>mvn test -Dtest=ProcessorTest
[INFO] Scanning for projects...
[INFO] 
[INFO] --< com.logicbig.example:mockito-verify-method-with-argument-matchers-example >--
[INFO] Building mockito-verify-method-with-argument-matchers-example 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ mockito-verify-method-with-argument-matchers-example ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\example-projects\mockito\verify-behavior\mockito-verify-method-with-argument-matchers-example\src\main\resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ mockito-verify-method-with-argument-matchers-example ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 2 source files to D:\example-projects\mockito\verify-behavior\mockito-verify-method-with-argument-matchers-example\target\classes
[INFO] 
[INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ mockito-verify-method-with-argument-matchers-example ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] skip non existing resourceDirectory D:\example-projects\mockito\verify-behavior\mockito-verify-method-with-argument-matchers-example\src\test\resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ mockito-verify-method-with-argument-matchers-example ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to D:\example-projects\mockito\verify-behavior\mockito-verify-method-with-argument-matchers-example\target\test-classes
[INFO] 
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ mockito-verify-method-with-argument-matchers-example ---
[INFO] Surefire report directory: D:\example-projects\mockito\verify-behavior\mockito-verify-method-with-argument-matchers-example\target\surefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.logicbig.example.ProcessorTest
My Integer is: 10
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.821 sec

Results :

Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  4.850 s
[INFO] Finished at: 2020-07-23T00:38:42-05:00
[INFO] ------------------------------------------------------------------------

Example Project

Dependencies and Technologies Used:

• mockito-core 3.3.3: Mockito mock objects library core API and implementation.
• junit 4.13: JUnit is a unit testing framework for Java, created by Erich Gamma and Kent Beck.
• JDK 8
• Maven 3.5.4