diff --git a/test/run.js b/test/run.js
index d679217..d4a9e7e 100644
--- a/test/run.js
+++ b/test/run.js
@@ -1,4 +1,6 @@
 import {tests} from './test.js'
-import {run} from './utils.js'
+
+// external
+import {run} from './run_utils.js'
 
 await run(tests)
diff --git a/test/run_utils.js b/test/run_utils.js
new file mode 100644
index 0000000..df7c261
--- /dev/null
+++ b/test/run_utils.js
@@ -0,0 +1,58 @@
+export const run = tests => {
+  // Runs test, return failure or null if not failed
+  const run_test = t => {
+    return Promise.resolve().then(t.test)
+      .then(() => null)
+      .catch(e => {
+        if(globalThis.process != null) {
+          // In node.js runner, fail fast
+          console.error('Failed: ' + t.message)
+          throw e
+        } else {
+          return e
+        }
+      })
+  }
+
+  // If not run in node, then dont apply filter
+  const filter = globalThis.process && globalThis.process.argv[2]
+
+  if(filter == null) {
+
+    const only = tests.find(t => t.only)
+    const tests_to_run = only == null ? tests : [only]
+
+    // Exec each test. After all tests are done, we rethrow first error if
+    // any. So we will mark root calltree node if one of tests failed
+    return tests_to_run.reduce(
+      (failureP, t) => 
+        Promise.resolve(failureP).then(failure => 
+          run_test(t).then(next_failure => failure ?? next_failure)
+        )
+      ,
+      null
+    ).then(failure => {
+
+      if(failure != null) {
+        throw failure
+      } else {
+        if(globalThis.process != null) {
+          console.log('Ok')
+        }
+      }
+
+    })
+
+  } else {
+    const test = tests.find(t => t.message.includes(filter))
+    if(test == null) {
+      throw new Error('test not found')
+    } else {
+      return run_test(test).then(() => {
+        if(globalThis.process != null) {
+          console.log('Ok')
+        }
+      })
+    }
+  }
+}
diff --git a/test/utils.js b/test/utils.js
index 8010396..a3a9626 100644
--- a/test/utils.js
+++ b/test/utils.js
@@ -234,66 +234,3 @@ export const test = (message, test, only = false) => {
 }
 
 export const test_only = (message, t) => test(message, t, true)
-
-// Wrap to Function constructor to hide from calltree view
-// TODO in calltree view, hide fn which has special flag set (see
-// filter_calltree)
-
-export const run = Object.defineProperty(new Function('tests', `
-    // Runs test, return failure or null if not failed
-    const run_test = t => {
-      return Promise.resolve().then(t.test)
-        .then(() => null)
-        .catch(e => {
-          if(globalThis.process != null) {
-            // In node.js runner, fail fast
-            console.error('Failed: ' + t.message)
-            throw e
-          } else {
-            return e
-          }
-        })
-    }
-
-    // If not run in node, then dont apply filter
-    const filter = globalThis.process && globalThis.process.argv[2]
-
-    if(filter == null) {
-
-      const only = tests.find(t => t.only)
-      const tests_to_run = only == null ? tests : [only]
-
-      // Exec each test. After all tests are done, we rethrow first error if
-      // any. So we will mark root calltree node if one of tests failed
-      return tests_to_run.reduce(
-        (failureP, t) => 
-          Promise.resolve(failureP).then(failure => 
-            run_test(t).then(next_failure => failure ?? next_failure)
-          )
-        ,
-        null
-      ).then(failure => {
-
-        if(failure != null) {
-          throw failure
-        } else {
-          if(globalThis.process != null) {
-            console.log('Ok')
-          }
-        }
-
-      })
-
-    } else {
-      const test = tests.find(t => t.message.includes(filter))
-      if(test == null) {
-        throw new Error('test not found')
-      } else {
-        return run_test(test).then(() => {
-          if(globalThis.process != null) {
-            console.log('Ok')
-          }
-        })
-      }
-    }
-`), 'name', {value: 'run'})