Removed thread-segregation from Variable and let.

src/main/java/com/greghaskins/spectrum/Variable.java

@@ -10,7 +10,7 @@
  */
 public final class Variable<T> implements Supplier<T> {
 
-  private ThreadLocal<T> value = new ThreadLocal<>();
+  private T value;
 
   /**
    * Create a Variable with a {@code null} initial value.
@@ -33,7 +33,7 @@ public Variable(final T value) {
    */
   @Override
   public T get() {
-    return this.value.get();
+    return this.value;
   }
 
   /**
@@ -42,6 +42,6 @@ public T get() {
    * @param value new value
    */
   public void set(final T value) {
-    this.value.set(value);
+    this.value = value;
   }
 }

src/test/java/specs/LetSpecs.java

@@ -182,8 +182,26 @@ public class LetSpecs {
             assertThat(result.getFailures().get(1).getMessage(), is("Bong!"));
           });
         });
+      });
+
+      describe("let across multiple threads", () -> {
+        final Supplier<List<String>> listSupplier = let(ArrayList::new);
+        it("can share the object with worker thread", () -> {
+          // when the supplier's object has something added to it
+          listSupplier.get().add("Hello world");
 
+          // used as a box for the integer
+          AtomicInteger atomicInteger = new AtomicInteger();
 
+          // when we access the object within a worker thread
+          Thread thread = new Thread(() -> atomicInteger.set(listSupplier.get().size()));
+          thread.start();
+          thread.join();
+
+          // then the worker thread saw the same object as the outer thread
+          // then the worker thread saw the same object as the outer thread
+          assertThat(atomicInteger.get(), is(1));
+        });
       });
     });
   }

src/test/java/specs/VariableSpecs.java

@@ -48,6 +48,17 @@ public class VariableSpecs {
         assertNull(name.get());
       });
 
+      it("has the same value across threads", () -> {
+        final Variable<String> outerVariable = new Variable<>("outer");
+        final Variable<String> whatWorkerThreadSees = new Variable<>();
+
+        Thread worker = new Thread(() -> whatWorkerThreadSees.set(outerVariable.get()));
+        worker.start();
+        worker.join();
+
+        assertThat(whatWorkerThreadSees.get(), is(outerVariable.get()));
+      });
+
     });
 
   }