### Question:
DefaultTokenStore implements TokenStore { @Override public String getValidAccessToken() { if (this.tokenSet == null) throw new IllegalStateException("Tokens must be set before requesting valid access token"); if (!this.tokenSet.isValid()) throw new IllegalStateException("Tokens are not valid"); return this.tokenSet.getAccessToken(); }  @Override void storeTokens(TokenSet tokenSet); @Override TokenSet getStoredTokens(); @Override String getValidAccessToken();  }### Answer:
@Test public void testGetValidAccessTokenNotSet() { thrown.expect(IllegalStateException.class); DefaultTokenStore store = new DefaultTokenStore(); store.getValidAccessToken(); }