Ignore assertions_on_result_states clippy lint

    error: called `assert!` with `Result::is_ok`
      --> tests/test_macros.rs:29:5
       |
    29 |     assert!(f().is_ok());
       |     ^^^^^^^^^^^^^^^^^^^^ help: replace with: `f().unwrap()`
       |
       = note: `-D clippy::assertions-on-result-states` implied by `-D clippy::all`
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assertions_on_result_states

    error: called `assert!` with `Result::is_ok`
      --> tests/test_macros.rs:36:5
       |
    36 |     assert!(f().is_ok());
       |     ^^^^^^^^^^^^^^^^^^^^ help: replace with: `f().unwrap()`
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assertions_on_result_states

    error: called `assert!` with `Result::is_err`
      --> tests/test_macros.rs:42:5
       |
    42 |     assert!(f().is_err());
       |     ^^^^^^^^^^^^^^^^^^^^^ help: replace with: `f().unwrap_err()`
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assertions_on_result_states

    error: called `assert!` with `Result::is_err`
       --> tests/test_downcast.rs:122:5
        |
    122 |     assert!(error.downcast::<&str>().is_err());
        |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `error.downcast::<&str>().unwrap_err()`
        |
        = note: `-D clippy::assertions-on-result-states` implied by `-D clippy::all`
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assertions_on_result_states

tests/test_downcast.rs

@@ -1,4 +1,4 @@
-#![allow(clippy::wildcard_imports)]
+#![allow(clippy::assertions_on_result_states, clippy::wildcard_imports)]
 
 mod common;
 mod drop;

tests/test_macros.rs

@@ -1,4 +1,5 @@
 #![allow(
+    clippy::assertions_on_result_states,
     clippy::eq_op,
     clippy::items_after_statements,
     clippy::needless_pass_by_value,