diff --git a/wasm/lib/Cargo.toml b/wasm/lib/Cargo.toml
index 00196be89..677fc5bbc 100644
--- a/wasm/lib/Cargo.toml
+++ b/wasm/lib/Cargo.toml
@@ -41,4 +41,4 @@ features = [
 ]
 
 [package.metadata.wasm-pack.profile.release]
-wasm-opt = ["-O1"]
+wasm-opt = false#["-O1"]
diff --git a/wasm/tests/test_exec_mode.py b/wasm/tests/test_exec_mode.py
index 669d7049d..a2a55846f 100644
--- a/wasm/tests/test_exec_mode.py
+++ b/wasm/tests/test_exec_mode.py
@@ -1,18 +1,21 @@
 def test_eval_mode(wdriver):
     assert wdriver.execute_script("return window.rp.pyEval('1+1')") == 2
 
+
 def test_exec_mode(wdriver):
     assert wdriver.execute_script("return window.rp.pyExec('1+1')") is None
 
+
 def test_exec_single_mode(wdriver):
     assert wdriver.execute_script("return window.rp.pyExecSingle('1+1')") == 2
-    assert wdriver.execute_script(
+    stdout = wdriver.execute_script(
         """
-        var output = [];
+        let output = "";
         save_output = function(text) {{
-           output.push(text)
+            output += text
         }};
         window.rp.pyExecSingle('1+1\\n2+2',{stdout: save_output});
         return output;
         """
-    ) == ["2\n", "4\n"]
+    )
+    assert stdout == "2\n4\n"
diff --git a/wasm/tests/test_inject_module.py b/wasm/tests/test_inject_module.py
index 462ed6535..afa25250d 100644
--- a/wasm/tests/test_inject_module.py
+++ b/wasm/tests/test_inject_module.py
@@ -19,4 +19,3 @@ assert mod.get_thing() == 1
 );
         """
     )
-