#1702 Consider that Vault permission handler may return null for permission groups

src/test/java/fr/xephi/authme/permission/handlers/VaultHandlerTest.java

@@ -0,0 +1,80 @@
+package fr.xephi.authme.permission.handlers;
+
+import net.milkbowl.vault.permission.Permission;
+import org.bukkit.Server;
+import org.bukkit.entity.Player;
+import org.junit.Test;
+
+import java.util.List;
+
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.empty;
+import static org.junit.Assert.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Test for {@link VaultHandler}.
+ */
+public class VaultHandlerTest {
+
+    private VaultHandlerTestImpl vaultHandlerTest = VaultHandlerTestImpl.create();
+
+    @Test
+    public void shouldReturnGroups() {
+        // given
+        Permission permissionMock = vaultHandlerTest.permissionMock;
+        Player player = mock(Player.class);
+        given(permissionMock.getPlayerGroups(null, player)).willReturn(new String[]{"abc", "test"});
+
+        // when
+        List<String> result = vaultHandlerTest.getGroups(player);
+
+        // then
+        assertThat(result, contains("abc", "test"));
+        verify(permissionMock).getPlayerGroups(null, player);
+    }
+
+    /**
+     * Bug #1702: VaultHandler may return null for groups list.
+     */
+    @Test
+    public void shouldHandleNullAsGroups() {
+        // given
+        Permission permissionMock = vaultHandlerTest.permissionMock;
+        Player player = mock(Player.class);
+        given(permissionMock.getPlayerGroups(null, player)).willReturn(null);
+
+        // when
+        List<String> result = vaultHandlerTest.getGroups(player);
+
+        // then
+        assertThat(result, empty());
+        verify(permissionMock).getPlayerGroups(null, player);
+    }
+
+    /** Test implementation using a mock Vault Permission instance. */
+    private static final class VaultHandlerTestImpl extends VaultHandler {
+
+        private Permission permissionMock;
+
+        VaultHandlerTestImpl() throws PermissionHandlerException {
+            super(null);
+        }
+
+        static VaultHandlerTestImpl create() {
+            try {
+                return new VaultHandlerTestImpl();
+            } catch (PermissionHandlerException e) {
+                throw new IllegalStateException(e);
+            }
+        }
+
+        @Override
+        Permission getVaultPermission(Server server) {
+            permissionMock = mock(Permission.class);
+            return permissionMock;
+        }
+    }
+}