add interface in core + move groupCollector to webapp

scm-webapp/src/test/java/sonia/scm/group/GroupCollectorTest.java

@@ -0,0 +1,60 @@
+package sonia.scm.group;
+
+import com.google.common.collect.Lists;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Nested;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import sonia.scm.security.GroupCollector;
+
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+class GroupCollectorTest {
+
+  @Mock
+  private GroupDAO groupDAO;
+
+  @InjectMocks
+  private GroupCollector collector;
+
+  @Test
+  void shouldAlwaysReturnAuthenticatedGroup() {
+    Iterable<String> groupNames = collector.collect("trillian");
+    assertThat(groupNames).containsOnly("_authenticated");
+  }
+
+  @Nested
+  class WithGroupsFromDao {
+
+    @BeforeEach
+    void setUpGroupsDao() {
+      List<Group> groups = Lists.newArrayList(
+        new Group("xml", "heartOfGold", "trillian"),
+        new Group("xml", "g42", "dent", "prefect"),
+        new Group("xml", "fjordsOfAfrican", "dent", "trillian")
+      );
+      when(groupDAO.getAll()).thenReturn(groups);
+    }
+
+    @Test
+    void shouldReturnGroupsFromDao() {
+      Iterable<String> groupNames = collector.collect("trillian");
+      assertThat(groupNames).contains("_authenticated", "heartOfGold", "fjordsOfAfrican");
+    }
+
+    @Test
+    void shouldCombineGivenWithDao() {
+      Iterable<String> groupNames = collector.collect("trillian");
+      assertThat(groupNames).contains("_authenticated", "heartOfGold", "fjordsOfAfrican", "awesome", "incredible");
+    }
+
+  }
+
+}