When putting an existing key/value pair then the original GitDbBranch finds the original value

src/main/java/net/kemitix/gitdb/impl/GitDBTransactionImpl.java

@@ -25,6 +25,7 @@ import com.github.zafarkhaja.semver.Version;
 import net.kemitix.gitdb.GitDBBranch;
 import net.kemitix.gitdb.GitDBTransaction;
 
+import java.io.IOException;
 import java.util.Optional;
 
 /**
@@ -48,8 +49,8 @@ class GitDBTransactionImpl implements GitDBTransaction {
     }
 
     @Override
-    public GitDBBranch put(String key, String value) {
-        return null;
+    public GitDBBranch put(String key, String value) throws IOException {
+        return branch.put(key, value);
     }
 
     @Override

src/test/java/net/kemitix/gitdb/test/GitDBTest.java

@@ -381,6 +381,19 @@ class GitDBTest implements WithAssertions {
     }
 
     // When putting an existing key/value pair then the original GitDbBranch finds the original value
+    @Test
+    void putValue_whenTransaction_thenUpdatedBranchFinds() throws IOException {
+        //given
+        final GitDBBranch originalBranch = gitDBBranch();
+        final GitDBTransaction transaction = originalBranch.transaction();
+        final String key = stringSupplier.get();
+        final String value = stringSupplier.get();
+        //when
+        final GitDBBranch updatedBranch = transaction.put(key, value);
+        //then
+        assertThat(updatedBranch.get(key)).contains(value);
+    }
+
     // When removing a key then the original GitDbBRanch still finds it
 
     // Given a GitDbTransaction handle with a added, updated and removed keys