#1031 Introduce hasSession field in datasource (#1351)

* Introduce hasSession field in datasource

That makes isLogged more consistent as it will be '1' only when the player is online.

* Fixes

* Fix unit testing

* Update config doc

* Create SessionService

* Create test for SessionService, avoid DB operations if sessions are disabled

* Cleanup: remove outdated warning for session timeout = 0
- Remove outdated warning
- Encapsulate session enabled check in SessionService

* Fix failing SessionServiceTest, add data source integration tests for session methods

src/test/java/fr/xephi/authme/datasource/AbstractDataSourceIntegrationTest.java

@@ -416,4 +416,36 @@ public abstract class AbstractDataSourceIntegrationTest {
         // then
         assertThat(loggedPlayersWithEmptyMail, contains("Bobby"));
     }
+
+    @Test
+    public void shouldGrantAndRetrieveSessionFlag() {
+        // given
+        DataSource dataSource = getDataSource();
+
+        // when
+        dataSource.grantSession("bobby");
+        dataSource.grantSession("doesNotExist");
+
+        // then
+        assertThat(dataSource.hasSession("bobby"), equalTo(true));
+        assertThat(dataSource.hasSession("user"), equalTo(false));
+        assertThat(dataSource.hasSession("bogus"), equalTo(false));
+    }
+
+    @Test
+    public void shouldRevokeSession() {
+        // given
+        DataSource dataSource = getDataSource();
+        dataSource.grantSession("bobby");
+        dataSource.grantSession("user");
+
+        // when
+        dataSource.revokeSession("bobby");
+        dataSource.revokeSession("userNotInDatabase");
+
+        // then
+        assertThat(dataSource.hasSession("bobby"), equalTo(false));
+        assertThat(dataSource.hasSession("user"), equalTo(true));
+        assertThat(dataSource.hasSession("nonExistentName"), equalTo(false));
+    }
 }