message: Enable these tests now that they pass.
  Also fix a syntax error, use assert_eq! instead of assert! to compare two values for equality.
  Also in passing, convert a comment about something not being done into a TODO.
diff: @@ -130,7 +130,7 @@ fn table_grow() -> Result<()> {
  #[test]
  #[ignore]
  fn table_copy() -> Result<()> {
  - // table copy test not yet implemented
  + // TODO: table copy test not yet implemented
  Ok(())
  }
  @@ -325,11 +325,9 @@ fn native_function_works() -> Result<()> {
  let result = native_function.call();
  assert!(result.is_ok());
  - // TODO:
  - /*let function = Function::new_native(&store, |a: i32| -> i32 { a + 1 });
  + let function = Function::new_native(&store, |a: i32| -> i32 { a + 1 });
  let native_function: NativeFunc<i32, i32> = function.native().unwrap();
  - assert!(native_function.call(3).unwrap(), 4);
  - */
  + assert_eq!(native_function.call(3).unwrap(), 4);
  fn rust_abi(a: i32, b: i64, c: f32, d: f64) -> u64 {
  (a as u64 * 1000) + (b as u64 * 100) + (c as u64 * 10) + (d as u64)
  @@ -342,15 +340,13 @@ fn native_function_works() -> Result<()> {
  let native_function: NativeFunc<(), i32> = function.native().unwrap();
  assert_eq!(native_function.call().unwrap(), 1);
  - // TODO:
  - /*let function = Function::new_native(&store, |_a: i32| {});
  + let function = Function::new_native(&store, |_a: i32| {});
  let native_function: NativeFunc<i32, ()> = function.native().unwrap();
  - assert!(native_function.call(4).is_ok());*/
  + assert!(native_function.call(4).is_ok());
  - // TODO:
  - /*let function = Function::new_native(&store, || -> (i32, i64, f32, f64) { (1, 2, 3.0, 4.0) });
  + let function = Function::new_native(&store, || -> (i32, i64, f32, f64) { (1, 2, 3.0, 4.0) });
  let native_function: NativeFunc<(), (i32, i64, f32, f64)> = function.native().unwrap();
  assert_eq!(native_function.call().unwrap(), (1, 2, 3.0, 4.0));
  - */
  +
  Ok(())
  }
  