Fix Jest globals not being available in non-entrypoint files (#17734)

src/bun.js/module_loader.zig

@@ -474,7 +474,7 @@ pub const RuntimeTranspilerStore = struct {
                 .virtual_source = null,
                 .dont_bundle_twice = true,
                 .allow_commonjs = true,
-                .inject_jest_globals = transpiler.options.rewrite_jest_for_tests and is_main,
+                .inject_jest_globals = transpiler.options.rewrite_jest_for_tests,
                 .set_breakpoint_on_first_line = vm.debugger != null and
                     vm.debugger.?.set_breakpoint_on_first_line and
                     is_main and
@@ -1623,7 +1623,7 @@ pub const ModuleLoader = struct {
                     .virtual_source = virtual_source,
                     .dont_bundle_twice = true,
                     .allow_commonjs = true,
-                    .inject_jest_globals = jsc_vm.transpiler.options.rewrite_jest_for_tests and is_main,
+                    .inject_jest_globals = jsc_vm.transpiler.options.rewrite_jest_for_tests,
                     .keep_json_and_toml_as_one_statement = true,
                     .allow_bytecode_cache = true,
                     .set_breakpoint_on_first_line = is_main and

test/regression/issue/12034/12034.fixture.ts

@@ -0,0 +1,25 @@
+// A fixture that tests that Jest globals are injected into the global scope
+// even when the file is NOT the entrypoint of the test.
+
+test.each([
+  ["expect", expect],
+  ["test", test],
+  ["describe", describe],
+  ["it", it],
+  ["beforeEach", beforeEach],
+  ["afterEach", afterEach],
+  ["beforeAll", beforeAll],
+  ["afterAll", afterAll],
+  ["jest", jest],
+])("that %s is defined", (_, global) => {
+  expect(global).toBeDefined();
+});
+
+expect.extend({
+  toBeOne(actual) {
+    return {
+      pass: actual === 1,
+      message: () => `expected ${actual} to be 1`,
+    };
+  },
+});

test/regression/issue/12034/12034.test.js

@@ -0,0 +1,8 @@
+// This fixture tests that Jest global variables are injected into the global scope
+// even when the file is NOT the entrypoint of the test.
+import "./12034.fixture";
+
+test("that an imported file can use Jest globals", () => {
+  expect(1).toBeOne();
+  expect(2).not.toBeOne();
+});