From f5ea3ad8d9f5201b8d498d0f4ca0712d2019cfef Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Thu, 25 Sep 2025 14:49:49 +0300
Subject: [PATCH 1/2] allow testing in production env

---
 .../samples/production/_config.js             |  5 ++
 .../samples/production/main.svelte            |  7 ++
 packages/svelte/tests/suite.ts                | 70 +++++++++++++++++--
 3 files changed, 78 insertions(+), 4 deletions(-)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/production/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/production/main.svelte

diff --git a/packages/svelte/tests/runtime-runes/samples/production/_config.js b/packages/svelte/tests/runtime-runes/samples/production/_config.js
new file mode 100644
index 000000000000..ce36c9d95b06
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/production/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	production: true
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/production/main.svelte b/packages/svelte/tests/runtime-runes/samples/production/main.svelte
new file mode 100644
index 000000000000..af1a8cd55ee3
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/production/main.svelte
@@ -0,0 +1,7 @@
+<script>
+    import { DEV } from "esm-env";
+console.info("prod", DEV)
+    if (DEV) {
+        throw new Error("Dev-only code must not run");
+    }
+</script>
\ No newline at end of file
diff --git a/packages/svelte/tests/suite.ts b/packages/svelte/tests/suite.ts
index bbd252b8e188..cbfab608ee20 100644
--- a/packages/svelte/tests/suite.ts
+++ b/packages/svelte/tests/suite.ts
@@ -1,9 +1,11 @@
 import fs from 'node:fs';
-import { it } from 'vitest';
+import { it, vi } from 'vitest';
 
 export interface BaseTest {
 	skip?: boolean;
 	solo?: boolean;
+	/** Set `DEV` to `false` */
+	production?: boolean;
 }
 
 /**
@@ -27,11 +29,33 @@ export function suite<Test extends BaseTest>(fn: (config: Test, test_dir: string
 	return {
 		test: (config: Test) => config,
 		run: async (cwd: string, samples_dir = 'samples') => {
+			const production_tests: Array<[Function, string, Function]> = [];
+
 			await for_each_dir<Test>(cwd, samples_dir, (config, dir) => {
 				let it_fn = config.skip ? it.skip : config.solo ? it.only : it;
 
-				it_fn(dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`));
+				if (config.production) {
+					production_tests.push([it_fn, dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`)]);
+				} else {
+					it_fn(dir, () => fn(config, `${cwd}/${samples_dir}/${dir}`));
+				}
 			});
+
+			if (production_tests.length) {
+				let mocked = false;
+				for (const [it, name, test] of production_tests) {
+					it(name, () => {
+						if (!mocked) {
+							vi.doMock('esm-env', async (importEnv) => ({
+								...(await importEnv()),
+								DEV: false
+							}));
+							mocked = true;
+						}
+						return test();
+					});
+				}
+			}
 		}
 	};
 }
@@ -45,6 +69,8 @@ export function suite_with_variants<Test extends BaseTest, Variants extends stri
 	return {
 		test: (config: Test) => config,
 		run: async (cwd: string, samples_dir = 'samples') => {
+			const production_tests: Array<[Function, string, Function]> = [];
+
 			await for_each_dir<Test>(cwd, samples_dir, (config, dir) => {
 				let called_common = false;
 				let common: any = undefined;
@@ -57,15 +83,37 @@ export function suite_with_variants<Test extends BaseTest, Variants extends stri
 					const solo = config.solo;
 					let it_fn = skip ? it.skip : solo ? it.only : it;
 
-					it_fn(`${dir} (${variant})`, async () => {
+					const test = async () => {
 						if (!called_common) {
 							called_common = true;
 							common = await common_setup(config, `${cwd}/${samples_dir}/${dir}`);
 						}
 						return fn(config, `${cwd}/${samples_dir}/${dir}`, variant, common);
-					});
+					};
+
+					if (config.production) {
+						production_tests.push([it_fn, `${dir} (${variant})`, test]);
+					} else {
+						it_fn(`${dir} (${variant})`, test);
+					}
 				}
 			});
+
+			if (production_tests.length) {
+				let mocked = false;
+				for (const [it, name, test] of production_tests) {
+					it(name, () => {
+						if (!mocked) {
+							vi.doMock('esm-env', async (importEnv) => ({
+								...(await importEnv()),
+								DEV: false
+							}));
+							mocked = true;
+						}
+						return test();
+					});
+				}
+			}
 		}
 	};
 }
@@ -108,3 +156,17 @@ export function assert_ok(value: any): asserts value {
 		throw new Error(`Expected truthy value, got ${value}`);
 	}
 }
+
+function run_in_production(fn: (...args: any[]) => void | Promise<void>) {
+	return async (...args: any[]) => {
+		vi.doMock('esm-env', async (importEnv) => ({
+			...(await importEnv()),
+			DEV: false
+		}));
+		try {
+			await fn(...args);
+		} finally {
+			vi.doUnmock('esm-env');
+		}
+	};
+}

From 872fa3a66cfc634dc392118fd247a4d7e0c0c747 Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Fri, 26 Sep 2025 21:48:55 +0300
Subject: [PATCH 2/2] oops

---
 .../samples/production/main.svelte            |  2 +-
 packages/svelte/tests/suite.ts                | 52 +++++++++----------
 2 files changed, 25 insertions(+), 29 deletions(-)

diff --git a/packages/svelte/tests/runtime-runes/samples/production/main.svelte b/packages/svelte/tests/runtime-runes/samples/production/main.svelte
index af1a8cd55ee3..d9cff745d15a 100644
--- a/packages/svelte/tests/runtime-runes/samples/production/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/production/main.svelte
@@ -1,6 +1,6 @@
 <script>
     import { DEV } from "esm-env";
-console.info("prod", DEV)
+
     if (DEV) {
         throw new Error("Dev-only code must not run");
     }
diff --git a/packages/svelte/tests/suite.ts b/packages/svelte/tests/suite.ts
index cbfab608ee20..72c40f526bc1 100644
--- a/packages/svelte/tests/suite.ts
+++ b/packages/svelte/tests/suite.ts
@@ -41,20 +41,18 @@ export function suite<Test extends BaseTest>(fn: (config: Test, test_dir: string
 				}
 			});
 
-			if (production_tests.length) {
-				let mocked = false;
-				for (const [it, name, test] of production_tests) {
-					it(name, () => {
-						if (!mocked) {
-							vi.doMock('esm-env', async (importEnv) => ({
-								...(await importEnv()),
-								DEV: false
-							}));
-							mocked = true;
-						}
-						return test();
-					});
-				}
+			let mocked = false;
+			for (const [it, name, test] of production_tests) {
+				it(name, () => {
+					if (!mocked) {
+						vi.doMock('esm-env', async (importEnv) => ({
+							...(await importEnv()),
+							DEV: false
+						}));
+						mocked = true;
+					}
+					return test();
+				});
 			}
 		}
 	};
@@ -99,20 +97,18 @@ export function suite_with_variants<Test extends BaseTest, Variants extends stri
 				}
 			});
 
-			if (production_tests.length) {
-				let mocked = false;
-				for (const [it, name, test] of production_tests) {
-					it(name, () => {
-						if (!mocked) {
-							vi.doMock('esm-env', async (importEnv) => ({
-								...(await importEnv()),
-								DEV: false
-							}));
-							mocked = true;
-						}
-						return test();
-					});
-				}
+			let mocked = false;
+			for (const [it, name, test] of production_tests) {
+				it(name, () => {
+					if (!mocked) {
+						vi.doMock('esm-env', async (importEnv) => ({
+							...(await importEnv()),
+							DEV: false
+						}));
+						mocked = true;
+					}
+					return test();
+				});
 			}
 		}
 	};