Register a platform for expression tests

worldedit-core/src/main/java/com/sk89q/worldedit/internal/expression/Expression.java

@@ -127,12 +127,15 @@ public class Expression {
             ((Variable) invokable).value = values[i];
         }
 
-        pushInstance();
-        try {
         Future<Double> result = evalThread.submit(new Callable<Double>() {
             @Override
             public Double call() throws Exception {
+                pushInstance();
+                try {
                     return root.getValue();
+                } finally {
+                    popInstance();
+                }
             }
         });
         try {
@@ -153,9 +156,6 @@ public class Expression {
             result.cancel(true);
             throw new EvaluationException(-1, "Calculations exceeded time limit.");
         }
-        } finally {
-            popInstance();
-        }
     }
 
     public void optimize() throws EvaluationException {

worldedit-core/src/test/java/com/sk89q/worldedit/internal/expression/ExpressionTest.java

@@ -24,13 +24,23 @@ import static java.lang.Math.sin;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
 
+import org.junit.Before;
+import org.junit.Test;
+
+import com.sk89q.worldedit.WorldEdit;
+import com.sk89q.worldedit.event.platform.PlatformReadyEvent;
 import com.sk89q.worldedit.internal.expression.lexer.LexerException;
 import com.sk89q.worldedit.internal.expression.parser.ParserException;
 import com.sk89q.worldedit.internal.expression.runtime.EvaluationException;
 import com.sk89q.worldedit.internal.expression.runtime.ExpressionEnvironment;
-import org.junit.Test;
 
 public class ExpressionTest {
+    @Before
+    public void setup() {
+        WorldEdit.getInstance().getPlatformManager().register(new ExpressionPlatform());
+        WorldEdit.getInstance().getPlatformManager().handlePlatformReady(new PlatformReadyEvent());
+    }
+
     @Test
     public void testEvaluate() throws ExpressionException {
         // check