1 files changed, 45 insertions, 0 deletions
diff --git a/object/id/objectid_test.go b/object/id/objectid_test.go
index 2559be0a..dc25832b 100644
--- a/object/id/objectid_test.go
+++ b/object/id/objectid_test.go
@@ -182,3 +182,48 @@ func TestAlgorithmSum(t *testing.T) {
 		t.Fatalf("sha1 and sha256 should differ")
 	}
 }
+
+func TestAlgorithmEmptyTree(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name string
+		algo objectid.Algorithm
+		want string
+	}{
+		{
+			name: "sha1",
+			algo: objectid.AlgorithmSHA1,
+			want: "4b825dc642cb6eb9a060e54bf8d69288fbee4904",
+		},
+		{
+			name: "sha256",
+			algo: objectid.AlgorithmSHA256,
+			want: "6ef19b41225c5369f1c104d45d8d85efa9b057b53b14b4b9b939dd74decc5321",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := tt.algo.EmptyTree()
+			if got.Algorithm() != tt.algo {
+				t.Fatalf("EmptyTree() algorithm = %v, want %v", got.Algorithm(), tt.algo)
+			}
+
+			if got.String() != tt.want {
+				t.Fatalf("EmptyTree() = %q, want %q", got.String(), tt.want)
+			}
+		})
+	}
+}
+
+func TestUnknownAlgorithmEmptyTree(t *testing.T) {
+	t.Parallel()
+
+	got := objectid.AlgorithmUnknown.EmptyTree()
+	if got != (objectid.ObjectID{}) {
+		t.Fatalf("EmptyTree() for unknown algorithm = %#v, want zero value", got)
+	}
+}