I am trying to use axios-mock-adapter to mock the response I get when calling the Spotify API to request an access token. Here is the function that does just that…

export const discovery = {
  authorizationEndpoint: "https://accounts.spotify.com/authorize",
  tokenEndpoint: "https://accounts.spotify.com/api/token",
};
...

export const getTokenRequest = async (response: AuthSessionResult, request: AuthRequest) => {  
  const accessCode  = response.params.code;
  console.log("Successfully authorised user and obtained access code", accessCode);
  await AsyncStorage.setItem("code", accessCode);

  const codeVerifier = request?.codeVerifier || ""
  console.log("Successfully obtained code verifier from request", codeVerifier);
  await AsyncStorage.setItem("codeVerifier", codeVerifier);

  const data = {
    client_id: clientId,
    grant_type: "authorization_code",
    code: accessCode,
    redirect_uri: redirectUri,
    code_verifier: codeVerifier
  }

  try {
    const tokenResponse = await axios.post(
      discovery.tokenEndpoint,
      qs.stringify(data),
      { 
        headers: {
        "Content-Type": "application/x-www-form-urlencoded",
        }
      })
    console.log("Successfully obtained token response", tokenResponse);

    storeAccessToken(tokenResponse);
    storeRefreshToken(tokenResponse);
  } catch(error) {
    console.log("Failed to obtain token request", error)
  }
}

…And here is my corresponding test…

  it("obtains an access code and a refresh token from the authorization code", async () => {
    const mockAxiosAdapter = new MockAdapter(axios);
    const mockTokenResponse = { data: { access_token: "DEF", refresh_token: "ABC" } };
    
    const authResult = { type: "success", params: { code: "123" } }
    const authRequest = { codeVerifier: "XYZ" }
 
    mockAxiosAdapter.onPost(AuthManager.discovery.tokenEndpoint).reply(200, mockTokenResponse);
    await AuthManager.getTokenRequest(authResult as AuthSessionResult, authRequest as AuthRequest);
    
    expect(AsyncStorage.setItem).toHaveBeenCalledWith("access_token", "DEF");
    expect(AsyncStorage.setItem).toHaveBeenCalledWith("refresh_token", "ABC");
  })
})

When running through this though, it does not seem that my mock post API call that I made is called, and instead, I get my tokenResponse being undefined. I debugged through it and it seems that my mock has been set up by axios-mock-adapter…

…And when I step into my function, it seems that everything has been set up alright on that front too…

But it does not work so I have come here to hopefully get unstuck! Thank you in advance for any help/insight on this problem!

EDIT: I have now posted this on the Github issues for axios-mock-adapter with an update . In short, I made an axios instance for my AuthManager. Doing this made it so that the axios instance is the same for both my getTokenRequest function and new MockAdapter(axios), but now it is not calling the mock and making an actual API call.