Added missing application/json content-type when calling Shlink with payload

test/common/services/HttpClient.test.ts

@@ -14,13 +14,39 @@ describe('HttpClient', () => {
       await expect(httpClient.fetchJson('')).rejects.toEqual(theError);
     });
 
-    it('return json on failure', async () => {
+    it.each([
+      [undefined],
+      [{}],
+      [{ body: undefined }],
+      [{ body: '' }],
+    ])('return json on failure', async (options) => {
       const theJson = { foo: 'bar' };
       fetch.mockResolvedValue({ json: () => theJson, ok: true });
 
-      const result = await httpClient.fetchJson('');
+      const result = await httpClient.fetchJson('the_url', options);
 
       expect(result).toEqual(theJson);
+      expect(fetch).toHaveBeenCalledWith('the_url', options);
+    });
+
+    it.each([
+      [{ body: 'the_body' }],
+      [{
+        body: 'the_body',
+        headers: {
+          'Content-Type': 'text/plain',
+        },
+      }],
+    ])('forwards JSON content-type when appropriate', async (options) => {
+      const theJson = { foo: 'bar' };
+      fetch.mockResolvedValue({ json: () => theJson, ok: true });
+
+      const result = await httpClient.fetchJson('the_url', options);
+
+      expect(result).toEqual(theJson);
+      expect(fetch).toHaveBeenCalledWith('the_url', expect.objectContaining({
+        headers: { 'Content-Type': 'application/json' },
+      }));
     });
   });