When getting a key that does not exist then return an empty Optional

src/main/java/net/kemitix/gitdb/GitDBBranch.java

@@ -25,6 +25,8 @@ import lombok.AccessLevel;
 import lombok.RequiredArgsConstructor;
 import org.eclipse.jgit.lib.Ref;
 
+import java.util.Optional;
+
 /**
  * API for interacting with a branch in a GirDB.
  *
@@ -44,4 +46,16 @@ public class GitDBBranch {
     public static GitDBBranch withRef(final Ref ref) {
         return new GitDBBranch(ref);
     }
+
+    /**
+     * Lookup a value for the key.
+     *
+     * @param key        the key to lookup
+     * @param valueClass the expected class of the value
+     * @param <T>        the Class of the value
+     * @return an Optional containing the value, if it exists, or empty if not
+     */
+    public <T> Optional<T> get(final String key, final Class<T> valueClass) {
+        return Optional.empty();
+    }
 }

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

@@ -1,5 +1,6 @@
 package net.kemitix.gitdb;
 
+import org.assertj.core.api.Assumptions;
 import org.assertj.core.api.WithAssertions;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
@@ -13,6 +14,8 @@ import java.io.*;
 import java.nio.file.*;
 import java.util.Optional;
 
+import static org.assertj.core.api.Assumptions.assumeThat;
+
 @ExtendWith(MockitoExtension.class)
 class GitDBTest implements WithAssertions {
 
@@ -193,6 +196,19 @@ class GitDBTest implements WithAssertions {
 
     // Given a valid GitDbBranch handle
     // When getting a key that does not exist then return an empty Optional
+    @Test
+    void getKey_whenKeyNotExist_thenReturnEmptyOptional() throws IOException {
+        //given
+        final GitDB gitDB = newGitDBRepo(dirDoesNotExist());
+        final Optional<GitDBBranch> branchOptional = gitDB.branch("master");
+        assumeThat(branchOptional).isNotEmpty();
+        final GitDBBranch master = branchOptional.get();
+        //when
+        final Optional<String> value = master.get("unknown", String.class);
+        //then
+        assertThat(value).isEmpty();
+    }
+
     // When putting a key/value pair then a GitDbBranch is returned
     // When getting a key that does exist then the value is returned inside an Optional
     // When removing a key that does not exist then the GitDbBranch is returned