Merge pull request #83 from marianobarrios/fix-build

Fix build: enable running without env. variables

Author: marianobarrios

build.gradle

@@ -32,18 +32,22 @@ java {
     withJavadocJar()
 }
 
+var testJavaToolchain = System.getenv('TEST_JAVA_TOOLCHAIN')
+
 testing {
     suites {
         test {
             useJUnitJupiter()
             targets {
                 all {
                     testTask.configure {
-                        javaLauncher.set(
-                                javaToolchains.launcherFor {
-                                    languageVersion.set(JavaLanguageVersion.of(System.getenv('TEST_JAVA_TOOLCHAIN')))
-                                }
-                        )
+                        if (testJavaToolchain != null) {
+                            javaLauncher.set(
+                                    javaToolchains.launcherFor {
+                                        languageVersion.set(JavaLanguageVersion.of(testJavaToolchain))
+                                    }
+                            )
+                        }
                     }
                 }
             }