Add test for throwing if there are no files found

Author: koddsson

packages/dynamic-import-vars/test/fixtures/fixture-no-files.js

@@ -0,0 +1,3 @@
+export function importModule(name) {
+  return import(`./module-dir-c/${name}.js`);
+}

packages/dynamic-import-vars/test/rollup-plugin-dynamic-import-vars.test.js

@@ -204,3 +204,29 @@ test('dynamic imports assertions', async (t) => {
   );
   t.snapshot(output[0].code);
 });
+
+test("doesn't throw if no files in dir when option isn't set", async (t) => {
+  let thrown = false;
+  try {
+    await rollup({
+      input: 'fixture-no-files.js',
+      plugins: [dynamicImportVars()]
+    });
+  } catch (_) {
+    thrown = true;
+  }
+  t.false(thrown);
+});
+
+test('throws if no files in dir when option is set', async (t) => {
+  let thrown = false;
+  try {
+    await rollup({
+      input: 'fixture-no-files.js',
+      plugins: [dynamicImportVars({ errorWhenNoFilesFound: true })]
+    });
+  } catch (_) {
+    thrown = true;
+  }
+  t.true(thrown);
+});

packages/dynamic-import-vars/test/snapshots/rollup-plugin-dynamic-import-vars.test.js.md

@@ -234,3 +234,25 @@ Generated by [AVA](https://avajs.dev).
     ␊
     export { importModule };␊
     `
+
+## no files in dir
+
+> Snapshot 1
+
+    `function __variableDynamicImportRuntime0__(path) {␊
+      switch (path) {␊
+    ␊
+        default: return new Promise(function(resolve, reject) {␊
+          (typeof queueMicrotask === 'function' ? queueMicrotask : setTimeout)(␊
+            reject.bind(null, new Error("Unknown variable dynamic import: " + path))␊
+          );␊
+        })␊
+       }␊
+     }␊
+    ␊
+    function importModule(name) {␊
+      return __variableDynamicImportRuntime0__(\`./module-dir-c/${name}.js\`);␊
+    }␊
+    ␊
+    export { importModule };␊
+    `