Added UT for `whoami` method in `WhoamiController.java`

provider/legal-azure/src/test/java/org/opengroup/osdu/legal/azure/security/WhoamiControllerTest.java

-package org.opengroup.osdu.legal.azure.security;public class WhoamiControllerTest {
+//  Copyright © Microsoft Corporation
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//       http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+package org.opengroup.osdu.legal.azure.security;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.InjectMocks;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.core.context.SecurityContext;
+
+import java.util.*;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.*;
+
+@RunWith(MockitoJUnitRunner.class)
+public class WhoamiControllerTest {
+
+    private static final String userName = "username";
+    private static final String roles = "roles";
+    private static final String details = "details";
+
+    @InjectMocks
+    private WhoamiController sut;
+
+    private class DummyPrincipal {
+        @Override
+        public String toString() {
+            return details;
+        }
+    }
+    public class DummyAuthority extends ArrayList {
+        @Override
+        public String toString() {
+            return roles;
+        }
+    }
+
+    @Before
+    public void init() {
+        Authentication auth = mock(Authentication.class);
+        SecurityContext securityContext = mock(SecurityContext.class);
+        doReturn(auth).when(securityContext).getAuthentication();
+        doReturn(userName).when(auth).getName();
+        doReturn(new DummyAuthority()).when(auth).getAuthorities();
+        doReturn(new DummyPrincipal()).when(auth).getPrincipal();
+        sut = new WhoamiController(securityContext);
+    }
+
+    @Test
+    public void testWhoamiResponse() {
+        String response = sut.whoami();
+        assertEquals("user: username<BR>roles: roles<BR>details: details<BR>", response);
+    }
 }