New testcases for Managers collections

Changes:
    - Added New test case:
      Verify Managers Collection With Unsupported Methods

Added Test cases on redfish/managers/test_managers_bmc.robot

Tested: Ran and Tested on BMC Environment

Change-Id: I33f5988e3babb3523c65fbad2ff7393624852146
Signed-off-by: Nandakumar B <nandakumarb@ami.com>
diff --git a/redfish/managers/test_managers_bmc.robot b/redfish/managers/test_managers_bmc.robot
index 3c8e6f4..ad05bee 100644
--- a/redfish/managers/test_managers_bmc.robot
+++ b/redfish/managers/test_managers_bmc.robot
@@ -185,6 +185,25 @@
     # TODO: Replace OCC state check with redfish property when available.
     Wait Until Keyword Succeeds  10 min  30 sec  Verify OCC State
 
+Verify Managers Collection Unsupported Methods
+    [Documentation]  Verify Managers Collection with Unsupported methods.
+    [Tags]  Verify_Manager_Collection_Unsupported_Methods
+
+    # Put operation on Managers Collection
+    Redfish.Put  /redfish/v1/Managers
+    ...  valid_status_codes=[${HTTP_METHOD_NOT_ALLOWED}]
+
+    # Post operation on Managers Collection
+    Redfish.Post  /redfish/v1/Managers
+    ...  valid_status_codes=[${HTTP_METHOD_NOT_ALLOWED}]
+
+    # Delete operation on Managers Collection
+    Redfish.Delete  /redfish/v1/Managers
+    ...  valid_status_codes=[${HTTP_METHOD_NOT_ALLOWED}]
+
+    # Patch operation on Managers Collection
+    Redfish.Patch  /redfish/v1/Managers
+    ...  valid_status_codes=[${HTTP_METHOD_NOT_ALLOWED}]
 
 *** Keywords ***