diff --git a/frontend_tests/zjsunit/finder.js b/frontend_tests/zjsunit/finder.js
deleted file mode 100644
index c1eadba325..0000000000
--- a/frontend_tests/zjsunit/finder.js
+++ /dev/null
@@ -1,47 +0,0 @@
-"use strict";
-
-const fs = require("fs");
-const path = require("path");
-
-const _ = require("lodash");
-
-exports.find_files_to_run = function () {
-    let oneFileFilter = [];
-    let testsDifference = [];
-    if (process.argv[2]) {
-        oneFileFilter = process.argv
-            .slice(2)
-            .filter((filename) => /[.]js$/.test(filename))
-            .map((filename) => filename.replace(/\.js$/i, ""));
-    }
-
-    // tests_dir is where we find our specific unit tests (as opposed
-    // to framework code)
-    const tests_dir = __dirname.replace(/zjsunit/, "node_tests");
-
-    let tests = fs
-        .readdirSync(tests_dir)
-        .filter((filename) => !/^\./i.test(filename))
-        .filter((filename) => /\.js$/i.test(filename))
-        .map((filename) => filename.replace(/\.js$/i, ""));
-
-    if (oneFileFilter.length > 0) {
-        tests = tests.filter((filename) => oneFileFilter.includes(filename));
-        testsDifference = _.difference(oneFileFilter, tests);
-    }
-
-    testsDifference.forEach((filename) => {
-        throw filename + ".js does not exist";
-    });
-
-    tests.sort();
-
-    const files = tests.map((fn) => {
-        const obj = {};
-        obj.name = fn;
-        obj.full_name = path.join(tests_dir, fn);
-        return obj;
-    });
-
-    return files;
-};
diff --git a/frontend_tests/zjsunit/index.js b/frontend_tests/zjsunit/index.js
index fbc685cccd..1790bc7c68 100644
--- a/frontend_tests/zjsunit/index.js
+++ b/frontend_tests/zjsunit/index.js
@@ -7,7 +7,6 @@ const path = require("path");
 const Handlebars = require("handlebars/runtime");
 const _ = require("lodash");
 
-const finder = require("./finder");
 const handlebars = require("./handlebars");
 const stub_i18n = require("./i18n");
 const namespace = require("./namespace");
@@ -34,7 +33,7 @@ function immediate(f) {
 }
 
 // Find the files we need to run.
-const files = finder.find_files_to_run(); // may write to console
+const files = process.argv.slice(2);
 if (files.length === 0) {
     throw "No tests found";
 }
@@ -100,9 +99,9 @@ global.markdown_assert = require("./markdown_assert");
 let current_file_name;
 
 function run_one_module(file) {
-    console.info("running tests for " + file.name);
-    current_file_name = file.name;
-    require(file.full_name);
+    console.info("running test " + path.basename(file, ".js"));
+    current_file_name = file;
+    require(file);
 }
 
 global.run_test = (label, f) => {
diff --git a/tools/test-js-with-node b/tools/test-js-with-node
index 1100020079..fcefc3d301 100755
--- a/tools/test-js-with-node
+++ b/tools/test-js-with-node
@@ -5,7 +5,7 @@ import os
 import pwd
 import subprocess
 import sys
-from typing import Any, Dict
+from typing import Any, Dict, List
 
 TOOLS_DIR = os.path.dirname(os.path.abspath(__file__))
 sys.path.insert(0, os.path.dirname(TOOLS_DIR))
@@ -203,24 +203,37 @@ def get_dev_host() -> str:
 def print_error(msg: str) -> None:
     print(BOLDRED + 'ERROR:' + ENDC + ' ' + msg)
 
+def clean_file(orig_fn: str) -> str:
+    fn = orig_fn
+    if not fn.endswith(".js"):
+        fn += ".js"
+    if "frontend_tests/" not in fn:
+        fn = os.path.join(ROOT_DIR, "frontend_tests", "node_tests", fn)
+    fn = os.path.abspath(fn)
+    if not os.path.exists(fn):
+        print(f"Cannot find {orig_fn} ({fn})")
+        sys.exit(1)
+    return fn
+
+def clean_files(fns: List[str]) -> List[str]:
+    cleaned_files = [clean_file(fn) for fn in fns]
+    return cleaned_files
+
 def run_tests_via_node_js() -> int:
     os.environ['TZ'] = 'UTC'
 
-    # Add ".js" to the end of all the file arguments, so index.js
-    # can actually verify if the file exists or not.
-    for index, arg in enumerate(options.args):
-        if not arg.endswith('.js') and not arg.endswith('.ts'):
-            # If it doesn't end with ".js" or ".ts", assume it is a JS file,
-            # since most files are currently JS files.
-            options.args[index] = arg + '.js'
-
     # The index.js test runner is the real "driver" here, and we launch
     # with either nyc or node, depending on whether we want coverage
     # reports.  Running under nyc is slower and creates funny
     # tracebacks, so you generally want to get coverage reports only
     # after making sure tests will pass.
     node_tests_cmd = ['node', '--stack-trace-limit=100', INDEX_JS]
-    node_tests_cmd += individual_files
+    if individual_files:
+        files = individual_files
+    else:
+        files = sorted(glob.glob("frontend_tests/node_tests/*.js"))
+
+    node_tests_cmd += clean_files(files)
     if options.coverage:
         coverage_dir = os.path.join(ROOT_DIR, 'var/node-coverage')