fix: add unit testing

src/platforms/npm-package/index.spec.ts

@@ -2,7 +2,7 @@
  * This is a sample test suite.
  * Replace this with your implementation.
  */
-import { readNpmPackageDependencies, analyze } from './index';
+import { readNpmPackageDependencies, countNpmPackageDependants, analyze } from './index';
 
 describe('Npm pacakge Tests', () => {
   it('should not read a non-existent package', async () => {
@@ -15,6 +15,14 @@ describe('Npm pacakge Tests', () => {
       { name: 'loose-envify', version: '^1.1.0' },
     ]);
   });
+  it('should count the depandants of a valid package', async () => {
+    await expect(countNpmPackageDependants('react', '18.3.1')).resolves.toEqual(10000);
+  });
+  it('can not count the depandants of a invalid package', async () => {
+    await expect(countNpmPackageDependants('is-a-non-existent-package', '1.0.0')).rejects.toEqual(
+      new Error(`Cannot count the depandants of the is-a-non-existent-package.`),
+    );
+  });
   it('can be analyzed for single package', async () => {
     await expect(analyze('react')).resolves.toMatchSnapshot();
   });

src/platforms/npm-package/index.ts

@@ -92,7 +92,7 @@ export async function countNpmPackageDependants(packageName: string, version: st
             retriedTimes += 1;
             doCountTask();
           } else {
-            reject(new Error(`Cannot read ${packageName}.`));
+            reject(new Error(`Cannot count the depandants of the ${packageName}.`));
           }
         })
         .finally(() => {
@@ -129,7 +129,7 @@ export async function analyze(packageNames: string): Promise<Dep[]> {
 
     const deps = await Promise.all(depsPromises);
     return Promise.resolve(deps);
-  } catch (error) {
-    return Promise.reject(new Error(`Cannot analyze ${packageNames}`));
+  } catch (error: any) {
+    return Promise.reject(new Error(`Cannot analyze ${packageNames}, the reason is ${error.message}`));
   }
 }

src/platforms/workspaces/yarn/index.spec.ts

@@ -21,7 +21,9 @@ describe('Workspaces Tests', () => {
     );
   });
   it('can not analyze for the invalid local packages', async () => {
-    await expect(analyze('./error-path')).rejects.toEqual(new Error(`Cannot analyze ./error-path`));
+    await expect(analyze('./error-path')).rejects.toEqual(
+      new Error(`Cannot analyze ./error-path, the reason is Cannot find package.json on ./error-path.`),
+    );
   });
   it('can be analyzed for the local packages', async () => {
     await expect(analyze('./src/platforms/workspaces/yarn/fixture/valid-packages')).resolves.toMatchSnapshot();

src/platforms/workspaces/yarn/index.ts

@@ -61,7 +61,7 @@ export async function analyze(packagePath: string) {
         };
       }),
     );
-  } catch (error) {
-    return Promise.reject(new Error(`Cannot analyze ${packagePath}`));
+  } catch (error: any) {
+    return Promise.reject(new Error(`Cannot analyze ${packagePath}, the reason is ${error.message}`));
   }
 }