diff --git a/tests/harness.js b/tests/harness.js
index a7efbf23..7299b719 100644
--- a/tests/harness.js
+++ b/tests/harness.js
@@ -96,9 +96,7 @@ LibAVTestHarness = {
         if (!opts && this.libav)
             return this.libav;
 
-        opts = opts || this.libAVOpts;
-
-        const ret = await LibAV.LibAV(opts);
+        const ret = await LibAV.LibAV(opts || this.libAVOpts);
         if (!opts)
             this.libav = ret;
 
@@ -159,9 +157,9 @@ LibAVTestHarness = {
                     await test.func(this);
                 } catch (ex) {
                     this.printErr("\n" +
-                        JSON.stringify(this.libAVOpts) + "\n" +
-                        test.name + "\n" +
-                        ex + "\n" + ex.stack);
+                        `Error in test ${test.name}\n` +
+                        "Options: " + JSON.stringify(this.libAVOpts) + "\n" +
+                        `Error: ${ex}\n${ex.stack}`);
                     fails++;
                 }
             }
diff --git a/tests/tests/003-utils.js b/tests/tests/003-utils.js
index 95998f97..514a09cd 100644
--- a/tests/tests/003-utils.js
+++ b/tests/tests/003-utils.js
@@ -37,7 +37,7 @@ h.utils.audioF32 = async function(file) {
         };
 
         await libav.ffmpeg(
-            "-nostdin", "-loglevel", "0",
+            "-nostdin", "-loglevel", "quiet",
             "-i", file,
             "-f", "f32le",
             "-ar", "48000",
@@ -48,7 +48,7 @@ h.utils.audioF32 = async function(file) {
     }
 
     if (file instanceof Array) {
-        if (file[0].data) {
+        if (file[0] && file[0].data) {
             if (file[0].data.buffer) {
                 // Frames of flat data
                 file = new Blob(file.map(x => x.data));
diff --git a/tests/tests/621-alt-variant.js b/tests/tests/621-alt-variant.js
index a12dbcf9..3b3f3da6 100644
--- a/tests/tests/621-alt-variant.js
+++ b/tests/tests/621-alt-variant.js
@@ -19,7 +19,12 @@
 let data;
 {
     const libav = await h.LibAV();
-    await libav.ffmpeg("-i", "bbb.webm", "-map", "0:a", "-c:a", "libvorbis", "tmp.ogg");
+    await libav.ffmpeg(
+        "-nostdin", "-loglevel", "quiet",
+        "-i", "bbb.webm",
+        "-map", "0:a", "-c:a", "libvorbis",
+        "tmp.ogg"
+    );
     data = await libav.readFile("tmp.ogg");
     await libav.unlink("tmp.ogg");
 }