diff --git a/examples/triangle_error.obj b/examples/triangle_error.obj
new file mode 100644
index 0000000..882a2a7
--- /dev/null
+++ b/examples/triangle_error.obj
@@ -0,0 +1,15 @@
+# Blender v2.91.0 OBJ File: ''
+# www.blender.org
+mtllib triangle.mtl
+o Plane
+v -1.000000 0.000000 0.000000
+v 1.000000 0.000000 1.000000
+v 1.000000 0.000000 -1.000000
+vt 0.000000 0.000000
+vt 1.000000 0.000000
+vt 1.000000 1.000000
+vn 0.0000 1.0000 0.0000
+usemtl None
+s off
+f 1/1/1 2/2/1 3/3/1
+invalid
diff --git a/src/obj.zig b/src/obj.zig
index 9f852cb..42c3249 100644
--- a/src/obj.zig
+++ b/src/obj.zig
@@ -141,6 +141,7 @@ pub fn parse(allocator: Allocator, data: []const u8) !ObjData {
 
     // current mesh material
     var current_material: ?MeshMaterial = null;
+    errdefer if (current_material) |mat| allocator.free(mat.material);
     var mesh_materials = ArrayList(MeshMaterial).init(allocator);
     errdefer mesh_materials.deinit();
     var num_processed_verts: usize = 0;
@@ -297,6 +298,7 @@ const test_allocator = std.testing.allocator;
 
 const expect = std.testing.expect;
 const expectError = std.testing.expectError;
+const expectEqual = std.testing.expectEqual;
 const expectEqualSlices = std.testing.expectEqualSlices;
 const expectEqualStrings = std.testing.expectEqualStrings;
 
@@ -308,60 +310,60 @@ test "comment" {
     var result = try parse(test_allocator, "# this is a comment");
     defer result.deinit(test_allocator);
 
-    try expect(result.vertices.len == 0);
-    try expect(result.tex_coords.len == 0);
-    try expect(result.normals.len == 0);
-    try expect(result.meshes.len == 0);
+    try expectEqual(0, result.vertices.len);
+    try expectEqual(0, result.tex_coords.len);
+    try expectEqual(0, result.normals.len);
+    try expectEqual(0, result.meshes.len);
 }
 
 test "single vertex def xyz" {
     var result = try parse(test_allocator, "v 0.123 0.234 0.345");
     defer result.deinit(test_allocator);
 
-    try expect(std.mem.eql(f32, result.vertices, &[_]f32{ 0.123, 0.234, 0.345 }));
-    try expect(result.tex_coords.len == 0);
-    try expect(result.normals.len == 0);
-    try expect(result.meshes.len == 0);
+    try expectEqualSlices(f32, &.{ 0.123, 0.234, 0.345 }, result.vertices);
+    try expectEqual(0, result.tex_coords.len);
+    try expectEqual(0, result.normals.len);
+    try expectEqual(0, result.meshes.len);
 }
 
 test "single vertex def xyzw" {
     var result = try parse(test_allocator, "v 0.123 0.234 0.345 0.456");
     defer result.deinit(test_allocator);
 
-    try expect(std.mem.eql(f32, result.vertices, &[_]f32{ 0.123, 0.234, 0.345 }));
-    try expect(result.tex_coords.len == 0);
-    try expect(result.normals.len == 0);
-    try expect(result.meshes.len == 0);
+    try expectEqualSlices(f32, &.{ 0.123, 0.234, 0.345 }, result.vertices);
+    try expectEqual(0, result.tex_coords.len);
+    try expectEqual(0, result.normals.len);
+    try expectEqual(0, result.meshes.len);
 }
 
 test "single tex coord def uv" {
     var result = try parse(test_allocator, "vt 0.123 0.234");
     defer result.deinit(test_allocator);
 
-    try expect(std.mem.eql(f32, result.tex_coords, &[_]f32{ 0.123, 0.234 }));
-    try expect(result.vertices.len == 0);
-    try expect(result.normals.len == 0);
-    try expect(result.meshes.len == 0);
+    try expectEqualSlices(f32, &.{ 0.123, 0.234 }, result.tex_coords);
+    try expectEqual(0, result.vertices.len);
+    try expectEqual(0, result.normals.len);
+    try expectEqual(0, result.meshes.len);
 }
 
 test "single tex coord def uvw" {
     var result = try parse(test_allocator, "vt 0.123 0.234 0.345");
     defer result.deinit(test_allocator);
 
-    try expect(std.mem.eql(f32, result.tex_coords, &[_]f32{ 0.123, 0.234 }));
-    try expect(result.vertices.len == 0);
-    try expect(result.normals.len == 0);
-    try expect(result.meshes.len == 0);
+    try expectEqualSlices(f32, &.{ 0.123, 0.234 }, result.tex_coords);
+    try expectEqual(0, result.vertices.len);
+    try expectEqual(0, result.normals.len);
+    try expectEqual(0, result.meshes.len);
 }
 
 test "single normal def xyz" {
     var result = try parse(test_allocator, "vn 0.123 0.234 0.345");
     defer result.deinit(test_allocator);
 
-    try expect(std.mem.eql(f32, result.normals, &[_]f32{ 0.123, 0.234, 0.345 }));
-    try expect(result.vertices.len == 0);
-    try expect(result.tex_coords.len == 0);
-    try expect(result.meshes.len == 0);
+    try expectEqualSlices(f32, &.{ 0.123, 0.234, 0.345 }, result.normals);
+    try expectEqual(0, result.vertices.len);
+    try expectEqual(0, result.tex_coords.len);
+    try expectEqual(0, result.meshes.len);
 }
 
 test "single face def vertex only" {
@@ -378,7 +380,7 @@ test "single face def vertex only" {
         },
         .materials = &[_]MeshMaterial{},
     };
-    try expect(result.meshes.len == 1);
+    try expectEqual(1, result.meshes.len);
     try expect(result.meshes[0].eq(mesh));
 }
 
@@ -396,7 +398,7 @@ test "single face def vertex + tex coord" {
         },
         .materials = &[_]MeshMaterial{},
     };
-    try expect(result.meshes.len == 1);
+    try expectEqual(1, result.meshes.len);
     try expect(result.meshes[0].eq(mesh));
 }
 
@@ -414,7 +416,7 @@ test "single face def vertex + tex coord + normal" {
         },
         .materials = &[_]MeshMaterial{},
     };
-    try expect(result.meshes.len == 1);
+    try expectEqual(1, result.meshes.len);
     try expect(result.meshes[0].eq(mesh));
 }
 
@@ -432,7 +434,7 @@ test "single face def vertex + normal" {
         },
         .materials = &[_]MeshMaterial{},
     };
-    try expect(result.meshes.len == 1);
+    try expectEqual(1, result.meshes.len);
     try expect(result.meshes[0].eq(expected));
 }
 
@@ -462,7 +464,7 @@ test "multiple materials in one mesh" {
         },
     };
 
-    try expect(result.meshes.len == 1);
+    try expectEqual(1, result.meshes.len);
     try expect(result.meshes[0].eq(expected));
 }
 
@@ -500,14 +502,14 @@ test "triangle obj exported from blender" {
             },
         },
     };
-    try expect(result.material_libs.len == 1);
-    try expectEqualStrings(result.material_libs[0], expected.material_libs[0]);
+    try expectEqual(1, result.material_libs.len);
+    try expectEqualStrings(expected.material_libs[0], result.material_libs[0]);
 
-    try expectEqualSlices(f32, result.vertices, expected.vertices);
-    try expectEqualSlices(f32, result.tex_coords, expected.tex_coords);
-    try expectEqualSlices(f32, result.normals, expected.normals);
+    try expectEqualSlices(f32, expected.vertices, result.vertices);
+    try expectEqualSlices(f32, expected.tex_coords, result.tex_coords);
+    try expectEqualSlices(f32, expected.normals, result.normals);
 
-    try expect(result.meshes.len == 1);
+    try expectEqual(1, result.meshes.len);
     try expect(result.meshes[0].eq(expected.meshes[0]));
 }
 
@@ -545,17 +547,22 @@ test "triangle obj exported from blender (windows line endings)" {
             },
         },
     };
-    try expect(result.material_libs.len == 1);
-    try expectEqualStrings(result.material_libs[0], expected.material_libs[0]);
+    try expectEqual(1, result.material_libs.len);
+    try expectEqualStrings(expected.material_libs[0], result.material_libs[0]);
 
-    try expectEqualSlices(f32, result.vertices, expected.vertices);
-    try expectEqualSlices(f32, result.tex_coords, expected.tex_coords);
-    try expectEqualSlices(f32, result.normals, expected.normals);
+    try expectEqualSlices(f32, expected.vertices, result.vertices);
+    try expectEqualSlices(f32, expected.tex_coords, result.tex_coords);
+    try expectEqualSlices(f32, expected.normals, result.normals);
 
-    try expect(result.meshes.len == 1);
+    try expectEqual(1, result.meshes.len);
     try expect(result.meshes[0].eq(expected.meshes[0]));
 }
 
+test "triangle obj exported from blender (with error)" {
+    const data = @embedFile("../examples/triangle_error.obj");
+    try expectError(error.UnknownDefType, parse(test_allocator, data));
+}
+
 test "cube obj exported from blender" {
     const data = @embedFile("../examples/cube.obj");
 
@@ -633,14 +640,14 @@ test "cube obj exported from blender" {
         },
     };
 
-    try expect(result.material_libs.len == 1);
-    try expectEqualStrings(result.material_libs[0], expected.material_libs[0]);
+    try expectEqual(1, result.material_libs.len);
+    try expectEqualStrings(expected.material_libs[0], result.material_libs[0]);
 
-    try expectEqualSlices(f32, result.vertices, expected.vertices);
-    try expectEqualSlices(f32, result.tex_coords, expected.tex_coords);
-    try expectEqualSlices(f32, result.normals, expected.normals);
+    try expectEqualSlices(f32, expected.vertices, result.vertices);
+    try expectEqualSlices(f32, expected.tex_coords, result.tex_coords);
+    try expectEqualSlices(f32, expected.normals, result.normals);
 
-    try expect(result.meshes.len == 1);
+    try expectEqual(1, result.meshes.len);
     try expect(result.meshes[0].eq(expected.meshes[0]));
 }