diff --git a/src/deflate/mod.rs b/src/deflate/mod.rs
index 6229eca9..ae51b847 100644
--- a/src/deflate/mod.rs
+++ b/src/deflate/mod.rs
@@ -89,7 +89,7 @@ pub fn cfzlib_deflate(
         }
         debug_assert!(stream.total_out as usize <= out.capacity());
         out.set_len(stream.total_out as usize);
-        return Ok(out);
+        Ok(out)
     }
 }
 
diff --git a/tests/flags.rs b/tests/flags.rs
index 13ab2c63..049e88b7 100644
--- a/tests/flags.rs
+++ b/tests/flags.rs
@@ -23,8 +23,8 @@ fn get_opts(input: &Path) -> (OutFile, oxipng::Options) {
 
 fn test_it_converts(
     input: PathBuf,
-    output: OutFile,
-    opts: oxipng::Options,
+    output: &OutFile,
+    opts: &oxipng::Options,
     color_type_in: ColorType,
     bit_depth_in: BitDepth,
     color_type_out: ColorType,
@@ -64,8 +64,8 @@ fn verbose_mode() {
 
     test_it_converts(
         input,
-        output,
-        opts,
+        &output,
+        &opts,
         ColorType::RGB,
         BitDepth::Eight,
         ColorType::RGB,
@@ -378,8 +378,8 @@ fn preserve_attrs() {
 
     test_it_converts(
         input,
-        output,
-        opts,
+        &output,
+        &opts,
         ColorType::RGB,
         BitDepth::Eight,
         ColorType::RGB,
@@ -430,8 +430,8 @@ fn zopfli_mode() {
 
     test_it_converts(
         input,
-        output,
-        opts,
+        &output,
+        &opts,
         ColorType::RGB,
         BitDepth::Eight,
         ColorType::RGB,