fix tests

packages/svelte/tests/runtime-legacy/samples/component-not-constructor2-dev/_config.js

@@ -16,8 +16,10 @@ export default test({
 			throw new Error('Expected an error');
 		} catch (err) {
 			assert.equal(
-				/** @type {Error} */ (err).message,
+				/** @type {Error} */ (err).message.includes(
 					'svelte_component_invalid_this_value\nThe `this={...}` property of a `<svelte:component>` must be a Svelte component, if defined'
+				),
+				true
 			);
 		}
 	}

packages/svelte/tests/runtime-legacy/samples/component-not-constructor2/_config.js

@@ -12,7 +12,10 @@ export default test({
 			component.componentName = 'banana';
 			throw new Error('Expected an error');
 		} catch (err) {
-			assert.equal(/** @type {Error} */ (err).message, '$$component is not a function');
+			assert.equal(
+				/** @type {Error} */ (err).message.includes('$$component is not a function'),
+				true
+			);
 		}
 	}
 });

packages/svelte/tests/runtime-legacy/shared.ts

@@ -392,9 +392,9 @@ async function run_test_variant(
 		}
 	} catch (err) {
 		if (config.runtime_error) {
-			assert.equal((err as Error).message, config.runtime_error);
+			assert.equal((err as Error).message.includes(config.runtime_error), true);
 		} else if (config.error && !unintended_error) {
-			assert.equal((err as Error).message, config.error);
+			assert.equal((err as Error).message.includes(config.error), true);
 		} else {
 			throw err;
 		}