Add test cases

Author: hkmatsumoto

tests/ui/unnecessary_wrap.fixed

@@ -42,20 +42,30 @@ fn func4() -> Option<i32> {
     Some(1)
 }
 
+// should not be linted
+fn func5() -> Option<i32> {
+    None
+}
+
 // should be linted
-fn func5() -> Result<i32, ()> {
+fn func6() -> Result<i32, ()> {
     Ok(1)
 }
 
 // should not be linted
-fn func6(a: bool) -> Result<i32, ()> {
+fn func7(a: bool) -> Result<i32, ()> {
     if a {
         Ok(1)
     } else {
         Err(())
     }
 }
 
+// should not be linted
+fn func8(a: bool) -> Result<i32, ()> {
+    Err(())
+}
+
 fn main() {
     // method calls are not linted
     func1(true, true);

tests/ui/unnecessary_wrap.rs

@@ -42,20 +42,30 @@ fn func4() -> Option<i32> {
     Some(1)
 }
 
+// should not be linted
+fn func5() -> Option<i32> {
+    None
+}
+
 // should be linted
-fn func5() -> Result<i32, ()> {
+fn func6() -> Result<i32, ()> {
     Ok(1)
 }
 
 // should not be linted
-fn func6(a: bool) -> Result<i32, ()> {
+fn func7(a: bool) -> Result<i32, ()> {
     if a {
         Ok(1)
     } else {
         Err(())
     }
 }
 
+// should not be linted
+fn func8(a: bool) -> Result<i32, ()> {
+    Err(())
+}
+
 fn main() {
     // method calls are not linted
     func1(true, true);

tests/ui/unnecessary_wrap.stderr

@@ -36,16 +36,16 @@ LL |     1
    |
 
 error: this function returns unnecessarily wrapping data
-  --> $DIR/unnecessary_wrap.rs:46:1
+  --> $DIR/unnecessary_wrap.rs:51:1
    |
-LL | / fn func5() -> Result<i32, ()> {
+LL | / fn func6() -> Result<i32, ()> {
 LL | |     Ok(1)
 LL | | }
    | |_^
    |
 help: factor this out to
    |
-LL | fn func5() -> i32 {
+LL | fn func6() -> i32 {
 LL |     1
    |