devonfw#78: the properties file stays stable. Wrote test

cli/src/test/java/com/devonfw/tools/ide/environment/EnvironmentVariablesPropertiesFileTest.java

@@ -1,6 +1,11 @@
 package com.devonfw.tools.ide.environment;
 
+import java.io.IOException;
+import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+import java.util.ArrayList;
+import java.util.List;
 
 import org.assertj.core.api.Assertions;
 import org.junit.jupiter.api.Test;
@@ -37,4 +42,96 @@ public void testLoad() {
     assertThat(variables.getVariables()).hasSize(4);
   }
 
+  @Test
+  void testSave() {
+
+    // arrange
+    List<String> linesToWrite = new ArrayList<>();
+    linesToWrite.add("# first comment");
+    linesToWrite.add("# second comment");
+    linesToWrite.add("var0=0");
+    linesToWrite.add("var1=1");
+    linesToWrite.add("var2=2");
+    linesToWrite.add("export var3=3");
+    linesToWrite.add("export var4=4");
+    linesToWrite.add("export var5=5");
+    linesToWrite.add("export var6=6");
+    linesToWrite.add("# third comment");
+    linesToWrite.add("var7=7");
+    linesToWrite.add("var8=8");
+    linesToWrite.add("# 4th comment");
+    linesToWrite.add("# 5th comment");
+    linesToWrite.add("var9=9");
+
+    Path propertiesFilePath = Path.of("src/test/resources/com/devonfw/tools/ide/env/var/ide.properties");
+    // Write to the file only if it does not exist
+    try {
+      Files.write(propertiesFilePath, linesToWrite, StandardOpenOption.CREATE_NEW);
+    } catch (IOException e) {
+      System.err.println("File already exists or an error occurred: " + e.getMessage());
+    }
+    // check if this writing was correct
+    try {
+      List<String> lines = Files.readAllLines(propertiesFilePath);
+      for (int i = 0; i < lines.size(); i++) {
+        assertThat(lines.get(i)).isEqualTo(linesToWrite.get(i));
+      }
+    } catch (IOException e) {
+      System.err.println("An error occurred: " + e.getMessage());
+    }
+
+    AbstractEnvironmentVariables parent = null;
+    EnvironmentVariablesType type = EnvironmentVariablesType.SETTINGS;
+
+    // act
+    EnvironmentVariablesPropertiesFile variables = new EnvironmentVariablesPropertiesFile(parent, type,
+        propertiesFilePath, LOGGER);
+
+    variables.set("var5", "5", true);
+    variables.set("var1", "1.0", false);
+    variables.set("var10", "10", false);
+    variables.set("var11", "11", true); // var11 must be set after var 10, the other lines can be shuffled
+    variables.set("var3", "3", false);
+    variables.set("var7", "7", true);
+    variables.set("var6", "6.0", true);
+    variables.set("var4", "4.0", false);
+    variables.set("var8", "8.0", true);
+
+    variables.save();
+
+    // assert
+    List<String> linesAfterSave = new ArrayList<>();
+    linesAfterSave.add("# first comment");
+    linesAfterSave.add("# second comment");
+    linesAfterSave.add("var0=0");
+    linesAfterSave.add("var1=1.0");
+    linesAfterSave.add("var2=2");
+    linesAfterSave.add("var3=3");
+    linesAfterSave.add("var4=4.0");
+    linesAfterSave.add("export var5=5");
+    linesAfterSave.add("export var6=6.0");
+    linesAfterSave.add("# third comment");
+    linesAfterSave.add("export var7=7");
+    linesAfterSave.add("export var8=8.0");
+    linesAfterSave.add("# 4th comment");
+    linesAfterSave.add("# 5th comment");
+    linesAfterSave.add("var9=9");
+    linesAfterSave.add("var10=10");
+    linesAfterSave.add("export var11=11");
+    try {
+      List<String> lines = Files.readAllLines(propertiesFilePath);
+      for (int i = 0; i < lines.size(); i++) {
+        assertThat(lines.get(i)).isEqualTo(linesAfterSave.get(i));
+      }
+    } catch (IOException e) {
+      System.err.println("An error occurred: " + e.getMessage());
+    }
+
+    // clean up
+    try {
+      Files.delete(propertiesFilePath);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+  }
 }