add descriptions to test cases

AmplifyPlugins/API/Tests/AWSAPIPluginTests/Support/Utils/Array+Error+TypeCastTests.swift

@@ -11,8 +11,11 @@ import XCTest
 
 class ArrayWithErrorElementExtensionTests: XCTestCase {
 
-
-
+    /**
+     Given: errors with generic protocol type
+     When: cast to the correct underlying concrete type
+     Then: successfully casted to underlying concrete type
+     */
     func testCast_toCorrectErrorType_returnCastedErrorType() {
         let errors: [Error] = [
             Error1(), Error1(), Error1()
@@ -24,6 +27,11 @@ class ArrayWithErrorElementExtensionTests: XCTestCase {
         XCTAssertEqual(errors.count, error1s!.count)
     }
 
+    /**
+     Given: errors with generic protocol type
+     When: cast to the wong underlying concrete type
+     Then: return nil
+     */
     func testCast_toWrongErrorType_returnNil() {
         let errors: [Error] = [
             Error1(), Error1(), Error1()
@@ -33,6 +41,12 @@ class ArrayWithErrorElementExtensionTests: XCTestCase {
         XCTAssertNil(error2s)
     }
 
+    /**
+     Given: errors with generic protocol type
+     When: some of the elements failed to cast to the underlying concrete type
+     Then: return nil
+     */
+
     func testCast_partiallyToWrongErrorType_returnNil() {
         let errors: [Error] = [
             Error2(), Error2(), Error1()