Make library created with cargo new clippy happy

Signed-off-by: hi-rustin <[email protected]>

Author: Rustin170506

src/cargo/ops/cargo_new.rs

@@ -812,7 +812,8 @@ fn main() {
 mod tests {
     #[test]
     fn it_works() {
-        assert_eq!(2 + 2, 4);
+        let result = 2 + 2;
+        assert_eq!(result, 4);
     }
 }
 "

tests/testsuite/init.rs

@@ -572,7 +572,8 @@ fn formats_source() {
 mod tests {
   #[test]
   fn it_works() {
-    assert_eq!(2 + 2, 4);
+    let result = 2 + 2;
+    assert_eq!(result, 4);
   }
 }
 "#
@@ -592,7 +593,8 @@ fn ignores_failure_to_format_source() {
 mod tests {
     #[test]
     fn it_works() {
-        assert_eq!(2 + 2, 4);
+        let result = 2 + 2;
+        assert_eq!(result, 4);
     }
 }
 "#

tests/testsuite/new.rs

@@ -31,7 +31,8 @@ fn simple_lib() {
 mod tests {
     #[test]
     fn it_works() {
-        assert_eq!(2 + 2, 4);
+        let result = 2 + 2;
+        assert_eq!(result, 4);
     }
 }
 "#