refactor: tests and makes `FregeDTOBuilder` a singleton

2 files changed, 25 insertions, 2 deletions

diff --git a/src/test/java/ch/fhnw/thga/gradleplugins/FregeDTOBuilder.java b/src/test/java/ch/fhnw/thga/gradleplugins/FregeDTOBuilder.java
index 5c24f10..f4cabbe 100644
--- a/src/test/java/ch/fhnw/thga/gradleplugins/FregeDTOBuilder.java
+++ b/src/test/java/ch/fhnw/thga/gradleplugins/FregeDTOBuilder.java
@@ -1,6 +1,6 @@
 package ch.fhnw.thga.gradleplugins;
 
-public class FregeDTOBuilder implements Builder {
+public final class FregeDTOBuilder implements Builder {
     private String version = "";
     private String release = "";
     private String compilerDownloadDir = "";
@@ -8,6 +8,23 @@ public class FregeDTOBuilder implements Builder {
     private String outputDir = "";
     private String mainModule = "";
 
+    private static volatile FregeDTOBuilder instance;
+
+    private FregeDTOBuilder() {
+    }
+
+    public static FregeDTOBuilder getInstance() {
+        FregeDTOBuilder result = instance;
+        if (result != null) {
+            return result;
+        } else {
+            synchronized (FregeDTOBuilder.class) {
+                return (instance == null) ? new FregeDTOBuilder() : instance;
+            }
+        }
+    }
+
+
     @Override
     public Builder version(String version) {
         this.version = version;
diff --git a/src/test/java/ch/fhnw/thga/gradleplugins/GradleBuildFileConversionTest.java b/src/test/java/ch/fhnw/thga/gradleplugins/GradleBuildFileConversionTest.java
index 80c8827..8512113 100644
--- a/src/test/java/ch/fhnw/thga/gradleplugins/GradleBuildFileConversionTest.java
+++ b/src/test/java/ch/fhnw/thga/gradleplugins/GradleBuildFileConversionTest.java
@@ -6,6 +6,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import java.util.stream.Stream;
 import java.util.stream.Collectors;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayNameGenerator;
 import org.junit.jupiter.api.IndicativeSentencesGeneration;
 import org.junit.jupiter.api.Nested;
@@ -15,7 +16,7 @@ import org.junit.jupiter.api.TestInstance.Lifecycle;
 
 @TestInstance(Lifecycle.PER_CLASS)
 public class GradleBuildFileConversionTest {
-    private final FregeDTOBuilder fregeBuilder = new FregeDTOBuilder();
+    private static FregeDTOBuilder fregeBuilder;
 
     private static String buildFilePluginString(String pluginId) {
         return String.format("id '%s'", pluginId);
@@ -30,6 +31,11 @@ public class GradleBuildFileConversionTest {
         assertTrue(subStrings.allMatch(substring -> s.contains(substring)));
     }
 
+    @BeforeEach
+    void setup() {
+        fregeBuilder = FregeDTOBuilder.getInstance();
+    }
+
     @Nested
     @IndicativeSentencesGeneration(separator = " -> ", generator = DisplayNameGenerator.ReplaceUnderscores.class)
     class Converting_Frege_DTO_to_build_file_key_value_pairs_works {