Use the TestPaths helper to lookup files.

javascript/extractor/test/com/semmle/js/extractor/test/ASTMatchingTests.java

@@ -12,6 +12,7 @@ import com.semmle.jcorn.SyntaxError;
 import com.semmle.js.ast.AST2JSON;
 import com.semmle.js.ast.Program;
 import com.semmle.util.io.WholeIO;
+import com.semmle.util.tests.TestPaths;
 import java.io.File;
 import java.util.Iterator;
 import java.util.Map.Entry;
@@ -54,7 +55,7 @@ public abstract class ASTMatchingTests {
     }
   }
 
-  private static final File BABYLON_BASE = new File("parser-tests/babylon").getAbsoluteFile();
+  private static final File BABYLON_BASE = TestPaths.get("parser-tests/babylon").toAbsolutePath().toFile();
 
   protected void babylonTest(String dir) {
     babylonTest(dir, new Options().esnext(true));

javascript/extractor/test/com/semmle/js/extractor/test/JSXTests.java

@@ -10,6 +10,7 @@ import com.semmle.js.ast.AST2JSON;
 import com.semmle.js.ast.Program;
 import com.semmle.util.files.FileUtil;
 import com.semmle.util.io.WholeIO;
+import com.semmle.util.tests.TestPaths;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.List;
@@ -25,7 +26,7 @@ import org.junit.runners.Parameterized.Parameters;
  */
 @RunWith(Parameterized.class)
 public class JSXTests extends ASTMatchingTests {
-  private static final File BASE = new File("parser-tests/jcorn-jsx").getAbsoluteFile();
+  private static final File BASE = TestPaths.get("parser-tests/jcorn-jsx").toAbsolutePath().toFile();
 
   @Parameters(name = "{0}")
   public static Iterable<Object[]> tests() {

javascript/extractor/test/com/semmle/js/extractor/test/RobustnessTests.java

@@ -3,6 +3,7 @@ package com.semmle.js.extractor.test;
 import com.semmle.jcorn.Options;
 import com.semmle.jcorn.Parser;
 import com.semmle.util.io.WholeIO;
+import com.semmle.util.tests.TestPaths;
 import java.io.File;
 import java.nio.charset.StandardCharsets;
 import org.junit.Test;
@@ -11,7 +12,7 @@ public class RobustnessTests {
 
   @Test
   public void letLookheadTest() {
-    File test = new File("parser-tests/robustness/letLookahead.js");
+    File test = TestPaths.get("parser-tests/robustness/letLookahead.js").toFile();
     String src = new WholeIO(StandardCharsets.UTF_8.name()).strictread(test);
     new Parser(new Options(), src, 0).parse();
   }

javascript/extractor/test/com/semmle/js/extractor/test/TrapTests.java

@@ -13,6 +13,7 @@ import com.semmle.util.extraction.ExtractorOutputConfig;
 import com.semmle.util.io.WholeIO;
 import com.semmle.util.process.Env;
 import com.semmle.util.srcarchive.DummySourceArchive;
+import com.semmle.util.tests.TestPaths;
 import com.semmle.util.trap.ITrapWriterFactory;
 import com.semmle.util.trap.TrapWriter;
 import com.semmle.util.trap.pathtransformers.ProjectLayoutTransformer;
@@ -35,7 +36,7 @@ import org.junit.runners.Parameterized.Parameters;
 
 @RunWith(Parameterized.class)
 public class TrapTests {
-  private static final File BASE = new File("tests").getAbsoluteFile();
+  private static final File BASE = TestPaths.get("tests").toAbsolutePath().toFile();
 
   @Parameters(name = "{0}:{1}")
   public static Iterable<Object[]> tests() {