[MNG-6776] Inconsistent list of parameters for MojoDescriptor (testcase)

maven-plugin-api/src/test/java/org/apache/maven/plugin/descriptor/MojoDescriptorTest.java

@@ -0,0 +1,36 @@
+package org.apache.maven.plugin.descriptor;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class MojoDescriptorTest
+{
+    @Test
+    public void getParameterMap() throws DuplicateParameterException
+    {
+        MojoDescriptor mojoDescriptor = new MojoDescriptor();
+        Parameter param1 = new Parameter();
+        param1.setName( "param1" );
+        param1.setDefaultValue( "value1" );
+        mojoDescriptor.addParameter( param1 );
+
+        List<Parameter> parameters = mojoDescriptor.getParameters();
+        assertEquals( 1, parameters.size() );
+
+        Map<String, Parameter> parameterMap = mojoDescriptor.getParameterMap();
+        assertEquals( parameters.size(), parameterMap.size() );
+
+        Parameter param2 = new Parameter();
+        param2.setName( "param2" );
+        param2.setDefaultValue( "value2" );
+        mojoDescriptor.addParameter( param2 );
+
+        assertEquals( 2, parameters.size() );
+        assertEquals( parameters.size(), parameterMap.size() );
+    }
+
+}