FinalizeLocalVariablesTest.java

package com.yourorg;

import org.junit.jupiter.api.Test;
import org.openrewrite.test.RecipeSpec;
import org.openrewrite.test.RewriteTest;

import static org.openrewrite.java.Assertions.java;

public class FinalizeLocalVariablesTest implements RewriteTest {
    @Override
    public void defaults(RecipeSpec spec) {
        spec.recipe(new FinalizeLocalVariables());
    }

    @Test
    void doesNotModifyReassignedVariables() {
        rewriteRun(
            java(
                """
                  class A {
                      public void test() {
                          int a = 0;
                          int b = 0;
                          for(int i = 0; i < 50; i++) {
                              a = i + 5;
                              b++;
                          }
                      }
                  }
                  """
            )
        );
    }

    @Test
    void doesNotModifyUninitializedVariables() {
        rewriteRun(
            java(
                """
                    class A {
                        void test() {
                            int a;
                            a = 0;
                        }
                    }
                    """
            )
        );
    }

    @Test
    void doesNotModifyLoopControlVariables() {
        rewriteRun(
            java(
                """
                    class A {
                        void test() {
                            for (int i = 0; i < 100; i++) {
                                System.out.println(i);
                            }
                        }
                    }
                    """
            )
        );
    }

    // aka "non-static fields"
    @Test
    void doesNotModifyInstanceVariables() {
        rewriteRun(
            java(
                """
                    class A {
                        int instanceVariableUninitialized;
                        int instanceVariableInitialized = 0;
                    }
                    """
            )
        );
    }

    // aka "static fields"
    @Test
    void doesNotModifyClassVariables() {
        rewriteRun(
            java(
                """
                    class A {
                        static int classVariableInitialized = 0;
                    }
                    """
            )
        );
    }

    @Test
    void doesNotModifyVariablesInCatchBlocks() {
        rewriteRun(
            java(
                """
                    import java.io.IOException;

                    class Test {
                        static {
                            try {
                                throw new IOException();
                            } catch (RuntimeException | IOException e) {
                                System.out.println("oops");
                            }
                        }
                    }
                    """
            )
        );
    }

    @Test
    void doesNotModifyVariablesInStaticInitializers() {
        rewriteRun(
            java(
                """
                    class Test {
                        static {
                            int n = 1;
                            for(int i = 0; i < n; i++) {
                            }
                        }
                    }
                    """
            )
        );
    }

    @Test
    void doesNotModifyVariablesCreatedInMethodParameters() {
        rewriteRun(
            java(
                """
                    class Test {
                        private static int testMath(int x, int y) {
                            y = y + y;
                            return x + y;
                        }
                        
                        public static void main(String[] args) { }
                    }
                    """
            )
        );
    }

    @Test
    void doesNotModifyLambdaVariables() {
        rewriteRun(
            java(
                """
                    import java.util.stream.Stream;

                    class A {
                        public boolean hasFoo(Stream<String> input) {
                            return input.anyMatch(word -> word.equalsIgnoreCase("foo"));
                        }
                    }
                    """
            )
        );
    }

    @Test
    void localVariablesAreMadeFinal() {
        rewriteRun(
            java(
                """
                    class A {
                        public void test() {
                            int n = 1;
                            for(int i = 0; i < n; i++) { }
                        }
                    }
                    """,
                """
                    class A {
                        public void test() {
                            final int n = 1;
                            for(int i = 0; i < n; i++) { }
                        }
                    }
                    """
            )
        );
    }

    @Test
    void localVariablesAreMadeFinalWithScopeAwareness() {
        rewriteRun(
            java(
                """
                    class Test {
                        public static void testA() {
                            int a = 0;
                            a = 1;
                        }
    
                        public static void testB() {
                            int a = 0;
                        }
                    }
                    """,
                """
                    class Test {
                        public static void testA() {
                            int a = 0;
                            a = 1;
                        }
    
                        public static void testB() {
                            final int a = 0;
                        }
                    }
                    """
            )
        );
    }

    @Test
    void nonModifyingUnaryOperatorAwareness() {
        rewriteRun(
            java(
                """
                  class Test {
                      void test() {
                          int i = 1;
                          int j = -i;
                          int k = +j;
                          int l = ~k;
                      }
                  }
                  """,
            """
                  class Test {
                      void test() {
                          final int i = 1;
                          final int j = -i;
                          final int k = +j;
                          final int l = ~k;
                      }
                  }
                  """
            )
        );
    }
}