feat(assert-function-name/auto-import): gracefully handle conflicts b…

…y renaming existing bindings

src/generate-assert-identifier.ts

@@ -37,6 +37,11 @@ const addImport = (
   source: string,
   name: string,
 ) => {
+  if (name) {
+    // clear possible binding conflicts
+    scope.rename(name);
+  }
+
   const program = scope.getProgramParent().path;
 
   // generate default or specified import from source

test/__snapshots__/assert-function-name.test.ts.snap

@@ -1,9 +1,26 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`does not rename non-conflicting bindings of the same name 1`] = `
+"import check from \\"power-assert\\";
+{
+  let check;
+}
+
+expect: check(1 === 1);"
+`;
+
 exports[`generates import with specified name when autoImport is set 1`] = `
 "import check from \\"power-assert\\";
 
 expect: check(1 === 1);"
 `;
 
 exports[`generates specified assert function 1`] = `"expect: check(1 === 1);"`;
+
+exports[`renames conflicting bindings when autoImporting 1`] = `
+"import check from \\"power-assert\\";
+
+let _check;
+
+expect: check(1 === 1);"
+`;

test/assert-function-name.test.ts

@@ -27,3 +27,45 @@ test('generates import with specified name when autoImport is set', () => {
   });
   expect(code).toMatchSnapshot();
 });
+
+test('renames conflicting bindings when autoImporting', () => {
+  const { code } = transform(
+    `let check;
+    expect: 1 === 1;`,
+    {
+      plugins: [
+        [
+          plugin,
+          {
+            ...minimalConfig,
+            assertFunctionName: 'check',
+            autoImport: true,
+          } as Config,
+        ],
+      ],
+    },
+  );
+  expect(code).toMatchSnapshot();
+});
+
+test('does not rename non-conflicting bindings of the same name', () => {
+  const { code } = transform(
+    `{
+      let check;
+    }
+    expect: 1 === 1;`,
+    {
+      plugins: [
+        [
+          plugin,
+          {
+            ...minimalConfig,
+            assertFunctionName: 'check',
+            autoImport: true,
+          } as Config,
+        ],
+      ],
+    },
+  );
+  expect(code).toMatchSnapshot();
+});