Bug 1842701 - Part 5: Add tests for devtools. r=nchevobbe,devtools-reviewers

Differential Revision: https://phabricator.services.mozilla.com/D184328

devtools/client/webconsole/test/browser/browser_jsterm_helpers_no_override.js

@@ -66,3 +66,78 @@ add_task(async function () {
 
   await resume(dbg);
 });
+
+add_task(async function () {
+  // Test the behavior when the variables are declared in the script.
+
+  const hud = await openNewTabAndConsole("data:text/html,Nothing");
+
+  let message = await executeAndWaitForResultMessage(
+    hud,
+    "var $ = 'var_$'; $",
+    "var_$"
+  );
+  ok(message, "$ was not overridden");
+
+  message = await executeAndWaitForResultMessage(
+    hud,
+    "const $$ = 'const_$$'; $$",
+    "const_$$"
+  );
+  ok(message, "$$ was not overridden");
+
+  message = await executeAndWaitForResultMessage(
+    hud,
+    "function keys() { return 'function_keys';  } keys()",
+    "function_keys"
+  );
+  ok(message, "keys was not overridden");
+
+  // Hoisted variable.
+  message = await executeAndWaitForResultMessage(
+    hud,
+    "{ var clear = 'var_clear';  } clear",
+    "var_clear"
+  );
+  ok(message, "clear was not overridden");
+
+  // Hoisted function.
+  message = await executeAndWaitForResultMessage(
+    hud,
+    "{ function help() { return 'function_help';  } } help()",
+    "function_help"
+  );
+  ok(message, "help was not overridden");
+
+  // Lexical variables are not hoisted.
+  message = await executeAndWaitForResultMessage(
+    hud,
+    "{ let values = 'let_values';  } typeof values",
+    "function"
+  );
+  ok(message, "values was not overridden because it's not global");
+});
+
+add_task(async function () {
+  // NOTE: Open a new page to use the same binding name again.
+
+  const hud = await openNewTabAndConsole("data:text/html,Nothing");
+
+  // An assignment on `globalThis` property inside the script doesn't shadow
+  // the helper binding.
+  let message = await executeAndWaitForResultMessage(
+    hud,
+    "globalThis.values = 'globalThis_values'; typeof values",
+    "function"
+  );
+  ok(message, "values was overridden because it's not declaration");
+
+  // Executing `values` again shadows the helper binding, given it exists
+  // before the execution.
+  message = await executeAndWaitForResultMessage(
+    hud,
+    "values",
+    "globalThis_values"
+  );
+  ok(message, "values was not overridden if it exists before the execution");
+});