diff --git a/quickjs-libc.c b/quickjs-libc.c
index e0d6594..10d3935 100644
--- a/quickjs-libc.c
+++ b/quickjs-libc.c
@@ -3965,8 +3965,6 @@ void js_std_add_helpers(JSContext *ctx, int argc, char **argv)
 
     JS_SetPropertyStr(ctx, global_obj, "print",
                       JS_NewCFunction(ctx, js_print, "print", 1));
-    JS_SetPropertyStr(ctx, global_obj, "__loadScript",
-                      JS_NewCFunction(ctx, js_loadScript, "__loadScript", 1));
 
     JS_FreeValue(ctx, global_obj);
 }
diff --git a/tests/assert.js b/tests/assert.js
new file mode 100644
index 0000000..c8240c8
--- /dev/null
+++ b/tests/assert.js
@@ -0,0 +1,49 @@
+export function assert(actual, expected, message) {
+    if (arguments.length === 1)
+        expected = true;
+
+    if (typeof actual === typeof expected) {
+        if (actual === expected) {
+            if (actual !== 0 || (1 / actual) === (1 / expected))
+                return;
+        }
+        if (typeof actual === 'number') {
+            if (isNaN(actual) && isNaN(expected))
+                return;
+        }
+        if (typeof actual === 'object') {
+            if (actual !== null && expected !== null
+            &&  actual.constructor === expected.constructor
+            &&  actual.toString() === expected.toString())
+                return;
+        }
+    }
+    throw Error("assertion failed: got |" + actual + "|" +
+                ", expected |" + expected + "|" +
+                (message ? " (" + message + ")" : ""));
+}
+
+export function assertThrows(err, func)
+{
+    var ex;
+    ex = false;
+    try {
+        func();
+    } catch(e) {
+        ex = true;
+        assert(e instanceof err);
+    }
+    assert(ex, true, "exception expected");
+}
+
+export function assertArrayEquals(a, b)
+{
+    if (!Array.isArray(a) || !Array.isArray(b))
+        return assert(false);
+
+    assert(a.length, b.length);
+
+    a.forEach((value, idx) => {
+        assert(b[idx], value);
+    });
+}
diff --git a/tests/test_bigint.js b/tests/test_bigint.js
index 0e67c8b..5fd1f91 100644
--- a/tests/test_bigint.js
+++ b/tests/test_bigint.js
@@ -1,39 +1,5 @@
-"use strict";
+import { assert, assertThrows } from "./assert.js";
 
-function assert(actual, expected, message) {
-    if (arguments.length == 1)
-        expected = true;
-
-    if (actual === expected)
-        return;
-
-    if (actual !== null && expected !== null
-    &&  typeof actual == 'object' && typeof expected == 'object'
-    &&  actual.toString() === expected.toString())
-        return;
-
-    throw Error("assertion failed: got |" + actual + "|" +
-                ", expected |" + expected + "|" +
-                (message ? " (" + message + ")" : ""));
-}
-
-function assertThrows(err, func)
-{
-    var ex;
-    ex = false;
-    try {
-        func();
-    } catch(e) {
-        ex = true;
-        assert(e instanceof err);
-    }
-    assert(ex, true, "exception expected");
-}
-
-// load more elaborate version of assert if available
-try { __loadScript("test_assert.js"); } catch(e) {}
-
-/*----------------*/
 
 function bigint_pow(a, n)
 {
@@ -89,8 +55,8 @@ function test_bigint1()
 
     a = bigint_pow(3n, 100n);
     assert((a - 1n) != a);
-    assert(a == 515377520732011331036461129765621272702107522001n);
-    assert(a == 0x5a4653ca673768565b41f775d6947d55cf3813d1n);
+    assert(a, 515377520732011331036461129765621272702107522001n);
+    assert(a, 0x5a4653ca673768565b41f775d6947d55cf3813d1n);
 
     r = 1n << 31n;
     assert(r, 2147483648n, "1 << 31n === 2147483648n");
diff --git a/tests/test_bjson.js b/tests/test_bjson.js
index 34c9b39..0a92162 100644
--- a/tests/test_bjson.js
+++ b/tests/test_bjson.js
@@ -1,21 +1,5 @@
 import * as bjson from "bjson";
-
-function assert(actual, expected, message) {
-    if (arguments.length == 1)
-        expected = true;
-
-    if (actual === expected)
-        return;
-
-    if (actual !== null && expected !== null
-    &&  typeof actual == 'object' && typeof expected == 'object'
-    &&  actual.toString() === expected.toString())
-        return;
-
-    throw Error("assertion failed: got |" + actual + "|" +
-                ", expected |" + expected + "|" +
-                (message ? " (" + message + ")" : ""));
-}
+import { assert } from "./assert.js";
 
 function toHex(a)
 {
@@ -196,12 +180,12 @@ function bjson_test_symbol()
     o = Symbol.for('foo');
     buf = bjson.write(o);
     r = bjson.read(buf, 0, buf.byteLength);
-    assert(o === r);
+    assert(o, r);
 
     o = Symbol.toStringTag;
     buf = bjson.write(o);
     r = bjson.read(buf, 0, buf.byteLength);
-    assert(o === r);
+    assert(o, r);
 }
 
 function bjson_test_all()
diff --git a/tests/test_builtin.js b/tests/test_builtin.js
index e02a0f7..0dbe243 100644
--- a/tests/test_builtin.js
+++ b/tests/test_builtin.js
@@ -1,4 +1,5 @@
 import * as os from "os";
+import { assert, assertThrows } from "./assert.js";
 
 // Keep this at the top; it tests source positions.
 function test_exception_source_pos()
@@ -6,21 +7,21 @@ function test_exception_source_pos()
     var e;
 
     try {
-        throw new Error(""); // line 9, column 19
+        throw new Error(""); // line 10, column 19
     } catch(_e) {
         e = _e;
     }
 
-    assert(e.stack.includes("test_builtin.js:9:19"));
+    assert(e.stack.includes("test_builtin.js:10:19"));
 }
 
 // Keep this at the top; it tests source positions.
-function test_function_source_pos() // line 18, column 1
+function test_function_source_pos() // line 19, column 1
 {
-    function inner() {} // line 20, column 5
+    function inner() {} // line 21, column 5
     var f = eval("function f() {} f");
-    assert(`${test_function_source_pos.lineNumber}:${test_function_source_pos.columnNumber}`, "18:1");
-    assert(`${inner.lineNumber}:${inner.columnNumber}`, "20:5");
+    assert(`${test_function_source_pos.lineNumber}:${test_function_source_pos.columnNumber}`, "19:1");
+    assert(`${inner.lineNumber}:${inner.columnNumber}`, "21:5");
     assert(`${f.lineNumber}:${f.columnNumber}`, "1:1");
 }
 
@@ -35,19 +36,19 @@ function test_exception_prepare_stack()
     };
 
     try {
-        throw new Error(""); // line 38, column 19
+        throw new Error(""); // line 39, column 19
     } catch(_e) {
         e = _e;
     }
 
     Error.prepareStackTrace = undefined;
 
-    assert(e.stack.length === 2);
+    assert(e.stack.length, 2);
     const f = e.stack[0];
-    assert(f.getFunctionName() === 'test_exception_prepare_stack');
+    assert(f.getFunctionName(), 'test_exception_prepare_stack');
     assert(f.getFileName().endsWith('test_builtin.js'));
-    assert(f.getLineNumber() === 38);
-    assert(f.getColumnNumber() === 19);
+    assert(f.getLineNumber(), 39);
+    assert(f.getColumnNumber(), 19);
     assert(!f.isNative());
 }
 
@@ -63,7 +64,7 @@ function test_exception_stack_size_limit()
     };
 
     try {
-        throw new Error(""); // line 66, column 19
+        throw new Error(""); // line 67, column 19
     } catch(_e) {
         e = _e;
     }
@@ -71,61 +72,15 @@ function test_exception_stack_size_limit()
     Error.stackTraceLimit = 10;
     Error.prepareStackTrace = undefined;
 
-    assert(e.stack.length === 1);
+    assert(e.stack.length, 1);
     const f = e.stack[0];
-    assert(f.getFunctionName() === 'test_exception_stack_size_limit');
+    assert(f.getFunctionName(), 'test_exception_stack_size_limit');
     assert(f.getFileName().endsWith('test_builtin.js'));
-    assert(f.getLineNumber() === 66);
-    assert(f.getColumnNumber() === 19);
+    assert(f.getLineNumber(), 67);
+    assert(f.getColumnNumber(), 19);
     assert(!f.isNative());
 }
 
-function assert(actual, expected, message) {
-    if (arguments.length == 1)
-        expected = true;
-
-    if (typeof actual === typeof expected) {
-        if (actual === expected) {
-            if (actual !== 0 || (1 / actual) === (1 / expected))
-                return;
-        }
-        if (typeof actual === 'number') {
-            if (isNaN(actual) && isNaN(expected))
-                return true;
-        }
-        if (typeof actual === 'object') {
-            if (actual !== null && expected !== null
-            &&  actual.constructor === expected.constructor
-            &&  actual.toString() === expected.toString())
-                return;
-        }
-    }
-    throw Error("assertion failed: got |" + actual + "|" +
-                ", expected |" + expected + "|" +
-                (message ? " (" + message + ")" : ""));
-}
-
-function assert_throws(expected_error, func)
-{
-    var err = false;
-    try {
-        func();
-    } catch(e) {
-        err = true;
-        if (!(e instanceof expected_error)) {
-            throw Error("unexpected exception type");
-        }
-    }
-    if (!err) {
-        throw Error("expected exception");
-    }
-}
-
-// load more elaborate version of assert if available
-try { __loadScript("test_assert.js"); } catch(e) {}
-
-/*----------------*/
-
 function my_func(a, b)
 {
     return a + b;
@@ -155,7 +110,7 @@ function test_function()
     r = (function () { return 1; }).apply(null, undefined);
     assert(r, 1);
 
-    assert_throws(TypeError, (function() {
+    assertThrows(TypeError, (function() {
         Reflect.apply((function () { return 1; }), null, undefined);
     }));
 
@@ -221,7 +176,7 @@ function test()
     assert(typeof a.y, "undefined", "extensible");
     assert(err, true, "extensible");
 
-    assert_throws(TypeError, () => Object.setPrototypeOf(Object.prototype, {}));
+    assertThrows(TypeError, () => Object.setPrototypeOf(Object.prototype, {}));
 }
 
 function test_enum()
@@ -1031,10 +986,10 @@ function test_cur_pc()
             get: function() { throw Error("a[1]_get"); },
             set: function(x) { throw Error("a[1]_set"); }
             });
-    assert_throws(Error, function() { return a[1]; });
-    assert_throws(Error, function() { a[1] = 1; });
-    assert_throws(Error, function() { return [...a]; });
-    assert_throws(Error, function() { return ({...b} = a); });
+    assertThrows(Error, function() { return a[1]; });
+    assertThrows(Error, function() { a[1] = 1; });
+    assertThrows(Error, function() { return [...a]; });
+    assertThrows(Error, function() { return ({...b} = a); });
 
     var o = {};
     Object.defineProperty(o, 'x', {
@@ -1042,34 +997,34 @@ function test_cur_pc()
             set: function(x) { throw Error("o.x_set"); }
             });
     o.valueOf = function() { throw Error("o.valueOf"); };
-    assert_throws(Error, function() { return +o; });
-    assert_throws(Error, function() { return -o; });
-    assert_throws(Error, function() { return o+1; });
-    assert_throws(Error, function() { return o-1; });
-    assert_throws(Error, function() { return o*1; });
-    assert_throws(Error, function() { return o/1; });
-    assert_throws(Error, function() { return o%1; });
-    assert_throws(Error, function() { return o**1; });
-    assert_throws(Error, function() { return o<<1; });
-    assert_throws(Error, function() { return o>>1; });
-    assert_throws(Error, function() { return o>>>1; });
-    assert_throws(Error, function() { return o&1; });
-    assert_throws(Error, function() { return o|1; });
-    assert_throws(Error, function() { return o^1; });
-    assert_throws(Error, function() { return o<1; });
-    assert_throws(Error, function() { return o==1; });
-    assert_throws(Error, function() { return o++; });
-    assert_throws(Error, function() { return o--; });
-    assert_throws(Error, function() { return ++o; });
-    assert_throws(Error, function() { return --o; });
-    assert_throws(Error, function() { return ~o; });
+    assertThrows(Error, function() { return +o; });
+    assertThrows(Error, function() { return -o; });
+    assertThrows(Error, function() { return o+1; });
+    assertThrows(Error, function() { return o-1; });
+    assertThrows(Error, function() { return o*1; });
+    assertThrows(Error, function() { return o/1; });
+    assertThrows(Error, function() { return o%1; });
+    assertThrows(Error, function() { return o**1; });
+    assertThrows(Error, function() { return o<<1; });
+    assertThrows(Error, function() { return o>>1; });
+    assertThrows(Error, function() { return o>>>1; });
+    assertThrows(Error, function() { return o&1; });
+    assertThrows(Error, function() { return o|1; });
+    assertThrows(Error, function() { return o^1; });
+    assertThrows(Error, function() { return o<1; });
+    assertThrows(Error, function() { return o==1; });
+    assertThrows(Error, function() { return o++; });
+    assertThrows(Error, function() { return o--; });
+    assertThrows(Error, function() { return ++o; });
+    assertThrows(Error, function() { return --o; });
+    assertThrows(Error, function() { return ~o; });
 
     Object.defineProperty(globalThis, 'xxx', {
             get: function() { throw Error("xxx_get"); },
             set: function(x) { throw Error("xxx_set"); }
             });
-    assert_throws(Error, function() { return xxx; });
-    assert_throws(Error, function() { xxx = 1; });
+    assertThrows(Error, function() { return xxx; });
+    assertThrows(Error, function() { xxx = 1; });
 }
 
 test();
diff --git a/tests/test_closure.js b/tests/test_closure.js
index f5d4160..4d63879 100644
--- a/tests/test_closure.js
+++ b/tests/test_closure.js
@@ -1,3 +1,5 @@
+// This test cannot use imports because it needs to run in non-strict mode.
+
 function assert(actual, expected, message) {
     if (arguments.length == 1)
         expected = true;
@@ -15,9 +17,6 @@ function assert(actual, expected, message) {
                 (message ? " (" + message + ")" : ""));
 }
 
-// load more elaborate version of assert if available
-try { __loadScript("test_assert.js"); } catch(e) {}
-
 /*----------------*/
 
 var log_str = "";
@@ -135,9 +134,9 @@ function test_arrow_function()
     assert(a.length, 2);
     assert(a[0] === 1 && a[1] === 2);
 
-    assert(f2.call("this_val") === "this_val");
-    assert(f3.call("this_val") === "this_val");
-    assert(new f4() === f4);
+    assert(f2.call("this_val"), "this_val");
+    assert(f3.call("this_val"), "this_val");
+    assert(new f4(), f4);
 
     var o1 = { f() { return this; } };
     var o2 = { f() {
@@ -145,7 +144,7 @@ function test_arrow_function()
     } };
     o2.__proto__ = o1;
 
-    assert(o2.f() === o2);
+    assert(o2.f(), o2);
 }
 
 function test_with()
@@ -153,20 +152,20 @@ function test_with()
     var o1 = { x: "o1", y: "o1" };
     var x = "local";
     eval('var z="var_obj";');
-    assert(z === "var_obj");
+    assert(z, "var_obj");
     with (o1) {
-        assert(x === "o1");
-        assert(eval("x") === "o1");
+        assert(x, "o1");
+        assert(eval("x"), "o1");
         var f = function () {
             o2 = { x: "o2" };
             with (o2) {
-                assert(x === "o2");
-                assert(y === "o1");
-                assert(z === "var_obj");
-                assert(eval("x") === "o2");
-                assert(eval("y") === "o1");
-                assert(eval("z") === "var_obj");
-                assert(eval('eval("x")') === "o2");
+                assert(x, "o2");
+                assert(y, "o1");
+                assert(z, "var_obj");
+                assert(eval("x"), "o2");
+                assert(eval("y"), "o1");
+                assert(eval("z"), "var_obj");
+                assert(eval('eval("x")'), "o2");
             }
         };
         f();
@@ -182,7 +181,7 @@ function test_eval_closure()
         eval("tab.push(function g1() { return i; })");
     }
     for(let i = 0; i < 3; i++) {
-        assert(tab[i]() === i);
+        assert(tab[i](), i);
     }
 
     tab = [];
@@ -193,7 +192,7 @@ function test_eval_closure()
         f();
     }
     for(let i = 0; i < 3; i++) {
-        assert(tab[i]() === i);
+        assert(tab[i](), i);
     }
 }
 
diff --git a/tests/test_language.js b/tests/test_language.js
index ad2dfe8..dbb4947 100644
--- a/tests/test_language.js
+++ b/tests/test_language.js
@@ -1,3 +1,5 @@
+// This test cannot use imports because it needs to run in non-strict mode.
+
 function assert(actual, expected, message) {
     if (arguments.length == 1)
         expected = true;
@@ -43,9 +45,6 @@ function assert_throws(expected_error, func, message)
     }
 }
 
-// load more elaborate version of assert if available
-try { __loadScript("test_assert.js"); } catch(e) {}
-
 /*----------------*/
 
 function test_op1()
@@ -119,20 +118,20 @@ function test_op1()
 
 function test_cvt()
 {
-    assert((NaN | 0) === 0);
-    assert((Infinity | 0) === 0);
-    assert(((-Infinity) | 0) === 0);
-    assert(("12345" | 0) === 12345);
-    assert(("0x12345" | 0) === 0x12345);
-    assert(((4294967296 * 3 - 4) | 0) === -4);
+    assert((NaN | 0), 0);
+    assert((Infinity | 0), 0);
+    assert(((-Infinity) | 0), 0);
+    assert(("12345" | 0), 12345);
+    assert(("0x12345" | 0), 0x12345);
+    assert(((4294967296 * 3 - 4) | 0), -4);
 
-    assert(("12345" >>> 0) === 12345);
-    assert(("0x12345" >>> 0) === 0x12345);
-    assert((NaN >>> 0) === 0);
-    assert((Infinity >>> 0) === 0);
-    assert(((-Infinity) >>> 0) === 0);
-    assert(((4294967296 * 3 - 4) >>> 0) === (4294967296 - 4));
-    assert((19686109595169230000).toString() === "19686109595169230000");
+    assert(("12345" >>> 0), 12345);
+    assert(("0x12345" >>> 0), 0x12345);
+    assert((NaN >>> 0), 0);
+    assert((Infinity >>> 0), 0);
+    assert(((-Infinity) >>> 0), 0);
+    assert(((4294967296 * 3 - 4) >>> 0), (4294967296 - 4));
+    assert((19686109595169230000).toString(), "19686109595169230000");
 }
 
 function test_eq()
@@ -317,36 +316,36 @@ function test_class()
         }
     }
 
-    assert(C.F() === -1);
+    assert(C.F(), -1);
     assert(Object.getOwnPropertyDescriptor(C.prototype, "y").get.name === "get y");
 
     o = new C();
-    assert(o.f() === 1);
-    assert(o.x === 10);
+    assert(o.f(), 1);
+    assert(o.x, 10);
 
-    assert(D.F() === -1);
-    assert(D.G() === -2);
-    assert(D.H() === -1);
+    assert(D.F(), -1);
+    assert(D.G(), -2);
+    assert(D.H(), -1);
 
     o = new D();
-    assert(o.f() === 1);
-    assert(o.g() === 2);
-    assert(o.x === 10);
-    assert(o.z === 20);
-    assert(o.h() === 1);
+    assert(o.f(), 1);
+    assert(o.g(), 2);
+    assert(o.x, 10);
+    assert(o.z, 20);
+    assert(o.h(), 1);
 
     /* test class name scope */
     var E1 = class E { static F() { return E; } };
-    assert(E1 === E1.F());
+    assert(E1, E1.F());
 
     class S {
         static x = 42;
         static y = S.x;
         static z = this.x;
     }
-    assert(S.x === 42);
-    assert(S.y === 42);
-    assert(S.z === 42);
+    assert(S.x, 42);
+    assert(S.y, 42);
+    assert(S.z, 42);
     
     class P {
         get;
@@ -357,10 +356,10 @@ function test_class()
         async = () => "789";
         static() { return 42; }
     }
-    assert(new P().get() === "123");
-    assert(new P().set() === "456");
-    assert(new P().async() === "789");
-    assert(new P().static() === 42);
+    assert(new P().get(), "123");
+    assert(new P().set(), "456");
+    assert(new P().async(), "789");
+    assert(new P().static(), 42);
 };
 
 function test_template()
@@ -390,7 +389,7 @@ function test_object_literal()
     var x = 0, get = 1, set = 2; async = 3;
     a = { get: 2, set: 3, async: 4, get a(){ return this.get} };
     assert(JSON.stringify(a), '{"get":2,"set":3,"async":4,"a":2}');
-    assert(a.a === 2);
+    assert(a.a, 2);
 
     a = { x, get, set, async };
     assert(JSON.stringify(a), '{"x":0,"get":1,"set":2,"async":3}');
@@ -400,10 +399,10 @@ function test_regexp_skip()
 {
     var a, b;
     [a, b = /abc\(/] = [1];
-    assert(a === 1);
+    assert(a, 1);
 
     [a, b =/abc\(/] = [2];
-    assert(a === 2);
+    assert(a, 2);
 }
 
 function test_labels()
diff --git a/tests/test_loop.js b/tests/test_loop.js
index 62b3e41..97fc2f6 100644
--- a/tests/test_loop.js
+++ b/tests/test_loop.js
@@ -1,3 +1,5 @@
+// This test cannot use imports because it needs to run in non-strict mode.
+
 function assert(actual, expected, message) {
     if (arguments.length == 1)
         expected = true;
@@ -15,9 +17,6 @@ function assert(actual, expected, message) {
                 (message ? " (" + message + ")" : ""));
 }
 
-// load more elaborate version of assert if available
-try { __loadScript("test_assert.js"); } catch(e) {}
-
 /*----------------*/
 
 function test_while()
@@ -29,7 +28,7 @@ function test_while()
         c++;
         i++;
     }
-    assert(c === 3);
+    assert(c, 3);
 }
 
 function test_while_break()
diff --git a/tests/test_queue_microtask.js b/tests/test_queue_microtask.js
index 106dde4..f06dc8b 100644
--- a/tests/test_queue_microtask.js
+++ b/tests/test_queue_microtask.js
@@ -1,57 +1,12 @@
-function assert(actual, expected, message) {
-    if (arguments.length == 1)
-        expected = true;
-
-    if (actual === expected)
-        return;
-
-    if (actual !== null && expected !== null
-    &&  typeof actual == 'object' && typeof expected == 'object'
-    &&  actual.toString() === expected.toString())
-        return;
-
-    throw Error("assertion failed: got |" + actual + "|" +
-                ", expected |" + expected + "|" +
-                (message ? " (" + message + ")" : ""));
-}
-
-function assert_throws(expected_error, func)
-{
-    var err = false;
-    try {
-        func();
-    } catch(e) {
-        err = true;
-        if (!(e instanceof expected_error)) {
-            throw Error("unexpected exception type");
-        }
-    }
-    if (!err) {
-        throw Error("expected exception");
-    }
-}
-
-function assert_array_equals(a, b) {
-    if (!Array.isArray(a) || !Array.isArray(b))
-        return assert(false);
-
-    assert(a.length === b.length);
-
-    a.forEach((value, idx) => {
-        assert(b[idx] === value);
-    });
-}
-
-// load more elaborate version of assert if available
-try { std.loadScript("test_assert.js"); } catch(e) {}
+import { assert, assertArrayEquals, assertThrows } from "./assert.js";
 
 function test_types() {
-  assert_throws(TypeError, () => queueMicrotask(), "no argument");
-  assert_throws(TypeError, () => queueMicrotask(undefined), "undefined");
-  assert_throws(TypeError, () => queueMicrotask(null), "null");
-  assert_throws(TypeError, () => queueMicrotask(0), "0");
-  assert_throws(TypeError, () => queueMicrotask({ handleEvent() { } }), "an event handler object");
-  assert_throws(TypeError, () => queueMicrotask("window.x = 5;"), "a string");
+  assertThrows(TypeError, () => queueMicrotask(), "no argument");
+  assertThrows(TypeError, () => queueMicrotask(undefined), "undefined");
+  assertThrows(TypeError, () => queueMicrotask(null), "null");
+  assertThrows(TypeError, () => queueMicrotask(0), "0");
+  assertThrows(TypeError, () => queueMicrotask({ handleEvent() { } }), "an event handler object");
+  assertThrows(TypeError, () => queueMicrotask("window.x = 5;"), "a string");
 }
 
 function test_async() {
@@ -74,7 +29,7 @@ function test_async_order() {
   queueMicrotask(() => happenings.push("b"));
   Promise.reject().catch(() => happenings.push("c"));
   queueMicrotask(() => {
-    assert_array_equals(happenings, ["a", "b", "c"]);
+    assertArrayEquals(happenings, ["a", "b", "c"]);
   });
 }
 
diff --git a/tests/test_std.js b/tests/test_std.js
index 3826308..7e9e2a4 100644
--- a/tests/test_std.js
+++ b/tests/test_std.js
@@ -1,30 +1,10 @@
 import * as std from "std";
 import * as os from "os";
+import { assert } from  "./assert.js";
 
 const isWin = os.platform === 'win32';
 const isCygwin = os.platform === 'cygwin';
 
-function assert(actual, expected, message) {
-    if (arguments.length == 1)
-        expected = true;
-
-    if (actual === expected)
-        return;
-
-    if (actual !== null && expected !== null
-    &&  typeof actual == 'object' && typeof expected == 'object'
-    &&  actual.toString() === expected.toString())
-        return;
-
-    throw Error("assertion failed: got |" + actual + "|" +
-                ", expected |" + expected + "|" +
-                (message ? " (" + message + ")" : ""));
-}
-
-// load more elaborate version of assert if available
-try { std.loadScript("test_assert.js"); } catch(e) {}
-
-/*----------------*/
 
 function test_printf()
 {
@@ -47,19 +27,19 @@ function test_file1()
 
     f.seek(0, std.SEEK_SET);
     str1 = f.readAsString();
-    assert(str1 === str);
+    assert(str1, str);
 
     f.seek(0, std.SEEK_END);
     size = f.tell();
-    assert(size === str.length);
+    assert(size, str.length);
 
     f.seek(0, std.SEEK_SET);
 
     buf = new Uint8Array(size);
     ret = f.read(buf.buffer, 0, size);
-    assert(ret === size);
+    assert(ret, size);
     for(i = 0; i < size; i++)
-        assert(buf[i] === str.charCodeAt(i));
+        assert(buf[i], str.charCodeAt(i));
 
     f.close();
 }
@@ -74,9 +54,9 @@ function test_file2()
         f.putByte(str.charCodeAt(i));
     f.seek(0, std.SEEK_SET);
     for(i = 0; i < size; i++) {
-        assert(str.charCodeAt(i) === f.getByte());
+        assert(str.charCodeAt(i), f.getByte());
     }
-    assert(f.getByte() === -1);
+    assert(f.getByte(), -1);
     f.close();
 }
 
@@ -97,11 +77,11 @@ function test_getline()
         line = f.getline();
         if (line === null)
             break;
-        assert(line == lines[line_count]);
+        assert(line, lines[line_count]);
         line_count++;
     }
     assert(f.eof());
-    assert(line_count === lines.length);
+    assert(line_count, lines.length);
 
     f.close();
 }
@@ -145,7 +125,7 @@ function test_os()
     os.remove(fdir);
 
     err = os.mkdir(fdir, 0o755);
-    assert(err === 0);
+    assert(err, 0);
 
     fd = os.open(fpath, os.O_RDWR | os.O_CREAT | os.O_TRUNC);
     assert(fd >= 0);
@@ -153,22 +133,22 @@ function test_os()
     buf = new Uint8Array(10);
     for(i = 0; i < buf.length; i++)
         buf[i] = i;
-    assert(os.write(fd, buf.buffer, 0, buf.length) === buf.length);
+    assert(os.write(fd, buf.buffer, 0, buf.length), buf.length);
 
-    assert(os.seek(fd, 0, std.SEEK_SET) === 0);
+    assert(os.seek(fd, 0, std.SEEK_SET), 0);
     buf2 = new Uint8Array(buf.length);
-    assert(os.read(fd, buf2.buffer, 0, buf2.length) === buf2.length);
+    assert(os.read(fd, buf2.buffer, 0, buf2.length), buf2.length);
 
     for(i = 0; i < buf.length; i++)
         assert(buf[i] == buf2[i]);
 
     if (typeof BigInt !== "undefined") {
         assert(os.seek(fd, BigInt(6), std.SEEK_SET), BigInt(6));
-        assert(os.read(fd, buf2.buffer, 0, 1) === 1);
+        assert(os.read(fd, buf2.buffer, 0, 1), 1);
         assert(buf[6] == buf2[0]);
     }
 
-    assert(os.close(fd) === 0);
+    assert(os.close(fd), 0);
 
     [files, err] = os.readdir(fdir);
     assert(err, 0);
@@ -186,7 +166,7 @@ function test_os()
 
     if (!isWin) {
         err = os.symlink(fname, link_path);
-        assert(err === 0);
+        assert(err, 0);
 
         [st, err] = os.lstat(link_path);
         assert(err, 0);
@@ -286,7 +266,7 @@ function test_timeout_order()
     function a() { s += "a"; os.setTimeout(c, 300); }
     function b() { s += "b"; }
     function c() { s += "c"; }
-    function d() { assert(s === "abc"); } // not "acb"
+    function d() { assert(s, "abc"); } // not "acb"
 }
 
 function test_stdio_close()
diff --git a/tests/test_worker.js b/tests/test_worker.js
index 818739e..bd0d0b9 100644
--- a/tests/test_worker.js
+++ b/tests/test_worker.js
@@ -1,23 +1,5 @@
-/* os.Worker API test */
-import * as std from "std";
 import * as os from "os";
-
-function assert(actual, expected, message) {
-    if (arguments.length == 1)
-        expected = true;
-
-    if (actual === expected)
-        return;
-
-    if (actual !== null && expected !== null
-    &&  typeof actual == 'object' && typeof expected == 'object'
-    &&  actual.toString() === expected.toString())
-        return;
-
-    throw Error("assertion failed: got |" + actual + "|" +
-                ", expected |" + expected + "|" +
-                (message ? " (" + message + ")" : ""));
-}
+import { assert } from "./assert.js";
 
 var worker;