feat: configurable filename separator for split command (#610)

* Make file path separator configurable in split command

* chore: add tests for the file name separator

* chore: update snapshots

* docs: split separator option description

* chore: code style fixes

packages/cli/src/commands/split/__tests__/index.test.ts

@@ -28,6 +28,7 @@ describe('#split', () => {
       {
         entrypoint: filePath,
         outDir: openapiDir,
+        separator: '_',
       }
     );
 
@@ -41,12 +42,31 @@ describe('#split', () => {
     );
   });
 
+
+  it('should use the correct separator', async () => {
+    const filePath = "./packages/cli/src/commands/split/__tests__/fixtures/spec.json";
+
+    const utils = require('../../../utils');
+    jest.spyOn(utils, 'pathToFilename').mockImplementation(() => 'newFilePath');
+
+    await handleSplit (
+      {
+        entrypoint: filePath,
+        outDir: openapiDir,
+        separator: '_',
+      }
+    );
+
+    expect(utils.pathToFilename).toBeCalledWith(expect.anything(), '_');
+    utils.pathToFilename.mockRestore();
+  });
+
   it('should have correct path with paths', () => {
     const openapi = require("./fixtures/spec.json");
     
     jest.spyOn(openapiCore, 'slash').mockImplementation(() => 'paths/test.yaml');
     jest.spyOn(path, 'relative').mockImplementation(() => 'paths/test.yaml');
-    iteratePathItems(openapi.paths, openapiDir, path.join(openapiDir, 'paths'), componentsFiles);
+    iteratePathItems(openapi.paths, openapiDir, path.join(openapiDir, 'paths'), componentsFiles, '_');
 
     expect(openapiCore.slash).toHaveBeenCalledWith('paths/test.yaml');
     expect(path.relative).toHaveBeenCalledWith('test', 'test/paths/test.yaml');