diff --git a/test/mjsunit/mjsunit.js b/test/mjsunit/mjsunit.js
index 111196264e..c1d46f6eaf 100644
--- a/test/mjsunit/mjsunit.js
+++ b/test/mjsunit/mjsunit.js
@@ -406,19 +406,18 @@ var failWithMessage;
 
 
   assertThrows = function assertThrows(code, type_opt, cause_opt) {
-    var threwException = true;
     try {
       if (typeof code === 'function') {
         code();
       } else {
         eval(code);
       }
-      threwException = false;
     } catch (e) {
       if (typeof type_opt === 'function') {
         assertInstanceof(e, type_opt);
       } else if (type_opt !== void 0) {
-        failWithMessage("invalid use of assertThrows, maybe you want assertThrowsEquals");
+        failWithMessage(
+            'invalid use of assertThrows, maybe you want assertThrowsEquals');
       }
       if (arguments.length >= 3) {
         assertEquals(e.message, cause_opt);
@@ -426,7 +425,7 @@ var failWithMessage;
       // Success.
       return;
     }
-    failWithMessage("Did not throw exception");
+    failWithMessage('Did not throw exception');
   };
 
 
diff --git a/test/mjsunit/wasm/indirect-calls.js b/test/mjsunit/wasm/indirect-calls.js
index 28effa8316..4c906a0110 100644
--- a/test/mjsunit/wasm/indirect-calls.js
+++ b/test/mjsunit/wasm/indirect-calls.js
@@ -74,7 +74,7 @@ module = (function () {
       kExprCallIndirect, sig_i_ii, kTableZero
     ])
     .exportFunc();
-  builder.appendToTable([mul.index, add.index, popcnt.index, main.index]);
+  builder.appendToTable([mul, add.index, popcnt.index, main.index]);
 
   return builder.instantiate({q: {mul: function(a, b) { return a * b | 0; }}});
 })();
diff --git a/test/mjsunit/wasm/wasm-constants.js b/test/mjsunit/wasm/wasm-constants.js
index e677f538d7..c71242a62c 100644
--- a/test/mjsunit/wasm/wasm-constants.js
+++ b/test/mjsunit/wasm/wasm-constants.js
@@ -339,36 +339,34 @@ let kTrapMsgs = [
 ];
 
 function assertTraps(trap, code) {
-    var threwException = true;
-    try {
-      if (typeof code === 'function') {
-        code();
-      } else {
-        eval(code);
-      }
-      threwException = false;
-    } catch (e) {
-      assertEquals("object", typeof e);
-      assertEquals(kTrapMsgs[trap], e.message);
-      // Success.
-      return;
+  try {
+    if (typeof code === 'function') {
+      code();
+    } else {
+      eval(code);
     }
-    throw new MjsUnitAssertionError("Did not trap, expected: " + kTrapMsgs[trap]);
+  } catch (e) {
+    assertEquals('object', typeof e);
+    assertEquals(kTrapMsgs[trap], e.message);
+    // Success.
+    return;
+  }
+  throw new MjsUnitAssertionError('Did not trap, expected: ' + kTrapMsgs[trap]);
 }
 
 function assertWasmThrows(value, code) {
-    assertEquals("number", typeof(value));
-    try {
-      if (typeof code === 'function') {
-        code();
-      } else {
-        eval(code);
-      }
-    } catch (e) {
-      assertEquals("number", typeof e);
-      assertEquals(value, e);
-      // Success.
-      return;
+  assertEquals('number', typeof value);
+  try {
+    if (typeof code === 'function') {
+      code();
+    } else {
+      eval(code);
     }
-    throw new MjsUnitAssertionError("Did not throw at all, expected: " + value);
+  } catch (e) {
+    assertEquals('number', typeof e);
+    assertEquals(value, e);
+    // Success.
+    return;
+  }
+  throw new MjsUnitAssertionError('Did not throw, expected: ' + value);
 }
diff --git a/test/mjsunit/wasm/wasm-module-builder.js b/test/mjsunit/wasm/wasm-module-builder.js
index 63f09a7370..49c812f3a7 100644
--- a/test/mjsunit/wasm/wasm-module-builder.js
+++ b/test/mjsunit/wasm/wasm-module-builder.js
@@ -98,7 +98,8 @@ class WasmFunctionBuilder {
 
   addBody(body) {
     for (let b of body) {
-      if (typeof b != 'number') throw new Error('invalid body: ' + body);
+      if (typeof b != 'number')
+        throw new Error('invalid body (entries have to be numbers): ' + body);
     }
     this.body = body;
     // Automatically add the end for the function block to the body.
@@ -264,6 +265,10 @@ class WasmModuleBuilder {
   }
 
   appendToTable(array) {
+    for (let n of array) {
+      if (typeof n != 'number')
+        throw new Error('invalid table (entries have to be numbers): ' + array);
+    }
     return this.addFunctionTableInit(this.function_table.length, false, array);
   }