testCases := []struct {
		volName     string
		expectedErr error
	}{
		// TestXLStorage case - 1.
		{
			volName:     "success-vol",
			expectedErr: nil,
		},
		// TestXLStorage case - 2.
		{
			volName:     "nonexistent-vol",
			expectedErr: errVolumeNotFound,
		},
		// TestXLStorage case - 3.
		{
			volName:     "ab",
			expectedErr: errVolumeNotFound,
		},
	}

		}
		// Failed as expected, but does it fail for the expected reason.
		if actualErr != nil && !testCase.shouldPass {
			if !strings.Contains(actualErr.Error(), testCase.expectedErr.Error()) {
				t.Errorf("Test %d: %s: Expected to fail with error \"%s\", but instead failed with error \"%s\" instead", i+1, instanceType, testCase.expectedErr.Error(), actualErr.Error())
			}
		}

		}

		value, err := webID.Retrieve()
		if err != nil && !testCase.expectedErr {
			c.Fatalf("Test %d: Expected to generate STS creds, got err: %#v", i+1, err)
		}
		if err == nil && testCase.expectedErr {
			c.Fatalf("Test %d: An error is unexpected to generate STS creds, got err: %#v", i+1, err)
		}

		if err != nil && testCase.expectedErr {
			continue
		}