use yadio for pricing "exotic" fiat (#921)

* yadio api

* add more currencies

* fix es typo

* bump version & fix cicleci build

.circleci/config.yml

@@ -3,7 +3,7 @@ jobs:
   build:
     working_directory: ~/code
     docker:
-      - image: cimg/android:2022.03-ndk
+      - image: cimg/android:2023.12-ndk
     environment:
       JVM_OPTS: -Xmx3200m
     steps:

app/build.gradle

@@ -8,8 +8,8 @@ android {
         compileSdk 33
         minSdkVersion 21
         targetSdkVersion 33
-        versionCode 3308
+        versionCode 3310
-        versionName "3.3.8 'Pocket Change'"
+        versionName "3.3.10 'Argentina'"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         externalNativeBuild {
             cmake {

app/src/main/java/com/m2049r/xmrwallet/XmrWalletApplication.java

@@ -22,18 +22,24 @@ import android.content.res.Configuration;
 import android.os.Build;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.OptIn;
 import androidx.fragment.app.FragmentManager;
+import androidx.fragment.app.FragmentStateManagerControl;
 
 import com.m2049r.xmrwallet.model.NetworkType;
 import com.m2049r.xmrwallet.util.LocaleHelper;
 import com.m2049r.xmrwallet.util.NetCipherHelper;
 import com.m2049r.xmrwallet.util.NightmodeHelper;
+import com.m2049r.xmrwallet.util.ServiceHelper;
+
+import java.util.Arrays;
 
 import timber.log.Timber;
 
 public class XmrWalletApplication extends Application {
 
     @Override
+    @OptIn(markerClass = FragmentStateManagerControl.class)
     public void onCreate() {
         super.onCreate();
         FragmentManager.enableNewStateManager(false);

app/src/main/java/com/m2049r/xmrwallet/service/exchange/api/ExchangeApi.java

@@ -33,5 +33,6 @@ public interface ExchangeApi {
     void queryExchangeRate(@NonNull final String baseCurrency, @NonNull final String quoteCurrency,
                            @NonNull final ExchangeCallback callback);
 
+    String getName();
 }
 

app/src/main/java/com/m2049r/xmrwallet/service/exchange/ecb/ExchangeApiImpl.java

@@ -67,9 +67,9 @@ public class ExchangeApiImpl implements ExchangeApi {
         // data is daily and is refreshed around 16:00 CET every working day
     }
 
-    public static boolean isSameDay(Calendar calendar, Calendar anotherCalendar) {
+    @Override
-        return (calendar.get(Calendar.YEAR) == anotherCalendar.get(Calendar.YEAR)) &&
+    public String getName() {
-                (calendar.get(Calendar.DAY_OF_YEAR) == anotherCalendar.get(Calendar.DAY_OF_YEAR));
+        return "ecb";
     }
 
     @Override
@@ -121,12 +121,12 @@ public class ExchangeApiImpl implements ExchangeApi {
         final NetCipherHelper.Request httpRequest = new NetCipherHelper.Request(baseUrl);
         httpRequest.enqueue(new okhttp3.Callback() {
             @Override
-            public void onFailure(final Call call, final IOException ex) {
+            public void onFailure(@NonNull final Call call, @NonNull final IOException ex) {
                 callback.onError(ex);
             }
 
             @Override
-            public void onResponse(final Call call, final Response response) throws IOException {
+            public void onResponse(@NonNull final Call call, @NonNull final Response response) throws IOException {
                 if (response.isSuccessful()) {
                     try {
                         DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
@@ -178,11 +178,12 @@ public class ExchangeApiImpl implements ExchangeApi {
                     Element cube = (Element) node;
                     if (cube.hasAttribute("time")) { // a time Cube
                         final Date time = DATE_FORMAT.parse(cube.getAttribute("time"));
+                        assert time != null;
                         date.setTime(time);
                     } else if (cube.hasAttribute("currency")
                             && cube.hasAttribute("rate")) { // a rate Cube
                         String currency = cube.getAttribute("currency");
-                        double rate = Double.valueOf(cube.getAttribute("rate"));
+                        double rate = Double.parseDouble(cube.getAttribute("rate"));
                         entries.put(currency, rate);
                     } // else an empty Cube - ignore
                 }
@@ -191,13 +192,10 @@ public class ExchangeApiImpl implements ExchangeApi {
             Timber.d(ex);
         }
         synchronized (this) {
-            if (date != null) {
             fetchDate = Calendar.getInstance(TimeZone.getTimeZone("CET"));
             fxDate = date;
             fxEntries.clear();
             fxEntries.putAll(entries);
         }
-            // else don't change what we have
-        }
     }
 }

app/src/main/java/com/m2049r/xmrwallet/service/exchange/kraken/ExchangeApiImpl.java

@@ -51,6 +51,11 @@ public class ExchangeApiImpl implements ExchangeApi {
         this(HttpUrl.parse("https://api.kraken.com/0/public/Ticker"));
     }
 
+    @Override
+    public String getName() {
+        return "kraken";
+    }
+
     @Override
     public void queryExchangeRate(@NonNull final String baseCurrency, @NonNull final String quoteCurrency,
                                   @NonNull final ExchangeCallback callback) {

app/src/main/java/com/m2049r/xmrwallet/service/exchange/krakenFiat/ExchangeApiImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019 m2049r@monerujo.io
+ * Copyright (c) 2019-2023 m2049r@monerujo.io
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@
 
 // https://developer.android.com/training/basics/network-ops/xml
 
-package com.m2049r.xmrwallet.service.exchange.krakenEcb;
+package com.m2049r.xmrwallet.service.exchange.krakenFiat;
 
 import androidx.annotation.NonNull;
 
@@ -24,23 +24,39 @@ import com.m2049r.xmrwallet.service.exchange.api.ExchangeApi;
 import com.m2049r.xmrwallet.service.exchange.api.ExchangeCallback;
 import com.m2049r.xmrwallet.service.exchange.api.ExchangeRate;
 import com.m2049r.xmrwallet.util.Helper;
+import com.m2049r.xmrwallet.util.ServiceHelper;
 
 import timber.log.Timber;
 
 /*
-    Gets the XMR/EUR rate from kraken and then gets the EUR/fiat rate from the ECB
+    Gets the XMR/EUR rate from kraken and then gets the EUR/fiat rate from the yadio
  */
 
 public class ExchangeApiImpl implements ExchangeApi {
     static public final String BASE_FIAT = "EUR";
 
+    final ExchangeApi krakenApi = new com.m2049r.xmrwallet.service.exchange.kraken.ExchangeApiImpl();
+
+    private ExchangeApi getFiatApi(String symbol) {
+        return ServiceHelper.getFiatApi(symbol);
+    }
+
+    @Override
+    public String getName() {
+        return krakenApi.getName() + "+";
+    }
+
+    public String getRealName(String fiatService) {
+        return getName() + fiatService;
+    }
+
     @Override
     public void queryExchangeRate(@NonNull final String baseCurrency, @NonNull final String quoteCurrency,
                                   @NonNull final ExchangeCallback callback) {
         Timber.d("B=%s Q=%s", baseCurrency, quoteCurrency);
         if (baseCurrency.equals(quoteCurrency)) {
             Timber.d("BASE=QUOTE=1");
-            callback.onSuccess(new ExchangeRateImpl(baseCurrency, quoteCurrency, 1.0));
+            callback.onSuccess(new ExchangeRateImpl(getName(), baseCurrency, quoteCurrency, 1.0));
             return;
         }
 
@@ -52,24 +68,21 @@ public class ExchangeApiImpl implements ExchangeApi {
 
         final String quote = Helper.BASE_CRYPTO.equals(baseCurrency) ? quoteCurrency : baseCurrency;
 
-        final ExchangeApi krakenApi =
-                new com.m2049r.xmrwallet.service.exchange.kraken.ExchangeApiImpl();
         krakenApi.queryExchangeRate(Helper.BASE_CRYPTO, BASE_FIAT, new ExchangeCallback() {
             @Override
             public void onSuccess(final ExchangeRate krakenRate) {
                 Timber.d("kraken = %f", krakenRate.getRate());
-                final ExchangeApi ecbApi =
+                final ExchangeApi fiatApi = getFiatApi(quote);
-                        new com.m2049r.xmrwallet.service.exchange.ecb.ExchangeApiImpl();
+                fiatApi.queryExchangeRate(BASE_FIAT, quote, new ExchangeCallback() {
-                ecbApi.queryExchangeRate(BASE_FIAT, quote, new ExchangeCallback() {
                     @Override
-                    public void onSuccess(final ExchangeRate ecbRate) {
+                    public void onSuccess(final ExchangeRate fiatRate) {
-                        Timber.d("ECB = %f", ecbRate.getRate());
+                        Timber.d("FIAT = %f", fiatRate.getRate());
-                        double rate = ecbRate.getRate() * krakenRate.getRate();
+                        double rate = fiatRate.getRate() * krakenRate.getRate();
                         Timber.d("Q=%s QC=%s", quote, quoteCurrency);
                         if (!quote.equals(quoteCurrency)) rate = 1.0d / rate;
                         Timber.d("rate = %f", rate);
                         final ExchangeRate exchangeRate =
-                                new ExchangeRateImpl(baseCurrency, quoteCurrency, rate);
+                                new ExchangeRateImpl(getRealName(fiatApi.getName()), baseCurrency, quoteCurrency, rate);
                         callback.onSuccess(exchangeRate);
                     }
 

app/src/main/java/com/m2049r/xmrwallet/service/exchange/krakenFiat/ExchangeRateImpl.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2019-2023 m2049r et al.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.m2049r.xmrwallet.service.exchange.krakenFiat;
+
+import androidx.annotation.NonNull;
+
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeApi;
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeRate;
+
+import lombok.Getter;
+
+class ExchangeRateImpl implements ExchangeRate {
+    @Getter
+    private final String serviceName;
+    @Getter
+    private final String baseCurrency;
+    @Getter
+    private final String quoteCurrency;
+    @Getter
+    private final double rate;
+
+    ExchangeRateImpl(@NonNull final String serviceName, @NonNull final String baseCurrency, @NonNull final String quoteCurrency, double rate) {
+        super();
+        this.serviceName = serviceName;
+        this.baseCurrency = baseCurrency;
+        this.quoteCurrency = quoteCurrency;
+        this.rate = rate;
+    }
+}

app/src/main/java/com/m2049r/xmrwallet/service/exchange/yadio/ExchangeApiImpl.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2019 m2049r@monerujo.io
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// https://developer.android.com/training/basics/network-ops/xml
+
+package com.m2049r.xmrwallet.service.exchange.yadio;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.VisibleForTesting;
+
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeApi;
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeCallback;
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeException;
+import com.m2049r.xmrwallet.util.NetCipherHelper;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import java.io.IOException;
+
+import okhttp3.Call;
+import okhttp3.HttpUrl;
+import okhttp3.Response;
+import timber.log.Timber;
+
+public class ExchangeApiImpl implements ExchangeApi {
+    @NonNull
+    private final HttpUrl baseUrl;
+
+    //so we can inject the mockserver url
+    @VisibleForTesting
+    public ExchangeApiImpl(@NonNull final HttpUrl baseUrl) {
+        this.baseUrl = baseUrl;
+    }
+
+    public ExchangeApiImpl() {
+        this(HttpUrl.parse("https://api.yadio.io/convert/1/eur"));
+    }
+
+    @Override
+    public String getName() {
+        return "yadio";
+    }
+
+    @Override
+    public void queryExchangeRate(@NonNull final String baseCurrency, @NonNull final String quoteCurrency,
+                                  @NonNull final ExchangeCallback callback) {
+        if (!baseCurrency.equals("EUR")) {
+            callback.onError(new IllegalArgumentException("Only EUR supported as base"));
+            return;
+        }
+
+        if (baseCurrency.equals(quoteCurrency)) {
+            callback.onSuccess(new ExchangeRateImpl(quoteCurrency, 1.0, 0));
+            return;
+        }
+
+        final HttpUrl url = baseUrl.newBuilder()
+                .addPathSegments(quoteCurrency.substring(0, 3))
+                .build();
+        final NetCipherHelper.Request httpRequest = new NetCipherHelper.Request(url);
+
+        httpRequest.enqueue(new okhttp3.Callback() {
+            @Override
+            public void onFailure(@NonNull final Call call, @NonNull final IOException ex) {
+                callback.onError(ex);
+            }
+
+            @Override
+            public void onResponse(@NonNull final Call call, @NonNull final Response response) throws IOException {
+                if (response.isSuccessful()) {
+                    try {
+                        assert response.body() != null;
+                        final JSONObject json = new JSONObject(response.body().string());
+                        if (json.has("error")) {
+                            Timber.d("%d: %s", response.code(), json.getString("error"));
+                            callback.onError(new ExchangeException(response.code(), json.getString("error")));
+                            return;
+                        }
+                        double rate = json.getDouble("rate");
+                        long timestamp = json.getLong("timestamp");
+                        callback.onSuccess(new ExchangeRateImpl(quoteCurrency, rate, timestamp));
+                    } catch (JSONException ex) {
+                        callback.onError(ex);
+                    }
+                } else {
+                    callback.onError(new ExchangeException(response.code(), response.message()));
+                }
+            }
+        });
+    }
+}

app/src/main/java/com/m2049r/xmrwallet/service/exchange/yadio/ExchangeRateImpl.java

@@ -14,41 +14,34 @@
  * limitations under the License.
  */
 
-package com.m2049r.xmrwallet.service.exchange.krakenEcb;
+package com.m2049r.xmrwallet.service.exchange.yadio;
 
 import androidx.annotation.NonNull;
 
 import com.m2049r.xmrwallet.service.exchange.api.ExchangeRate;
 
+import java.util.Date;
+
+import lombok.Getter;
+
 class ExchangeRateImpl implements ExchangeRate {
-    private final String baseCurrency;
+    @Getter
+    private final String baseCurrency = "EUR";
+    @Getter
     private final String quoteCurrency;
+    @Getter
     private final double rate;
+    private final Date date;
 
     @Override
     public String getServiceName() {
-        return "kraken+ecb";
+        return "yadio.io";
     }
 
-    @Override
+    ExchangeRateImpl(@NonNull final String quoteCurrency, double rate, final long timestamp) {
-    public String getBaseCurrency() {
-        return baseCurrency;
-    }
-
-    @Override
-    public String getQuoteCurrency() {
-        return quoteCurrency;
-    }
-
-    @Override
-    public double getRate() {
-        return rate;
-    }
-
-    ExchangeRateImpl(@NonNull final String baseCurrency, @NonNull final String quoteCurrency, double rate) {
         super();
-        this.baseCurrency = baseCurrency;
         this.quoteCurrency = quoteCurrency;
         this.rate = rate;
+        this.date = timestamp > 0 ? new Date(timestamp) : new Date();
     }
 }

app/src/main/java/com/m2049r/xmrwallet/util/ServiceHelper.java

@@ -1,9 +1,16 @@
 package com.m2049r.xmrwallet.util;
 
+import com.m2049r.xmrwallet.R;
 import com.m2049r.xmrwallet.model.NetworkType;
 import com.m2049r.xmrwallet.model.WalletManager;
 import com.m2049r.xmrwallet.service.exchange.api.ExchangeApi;
 
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import lombok.Getter;
+import lombok.NonNull;
 import okhttp3.HttpUrl;
 
 public class ServiceHelper {
@@ -19,6 +26,14 @@ public class ServiceHelper {
     }
 
     static public ExchangeApi getExchangeApi() {
-        return new com.m2049r.xmrwallet.service.exchange.krakenEcb.ExchangeApiImpl();
+        return new com.m2049r.xmrwallet.service.exchange.krakenFiat.ExchangeApiImpl();
+    }
+
+    static private final ExchangeApi[] fiatApis = new ExchangeApi[]{
+            new com.m2049r.xmrwallet.service.exchange.ecb.ExchangeApiImpl(),
+            new com.m2049r.xmrwallet.service.exchange.yadio.ExchangeApiImpl()};
+
+    static public ExchangeApi getFiatApi(String symbol) {
+        return (symbol.length() == 3) ? fiatApis[0] : fiatApis[1];
     }
 }

app/src/main/res/values-es/strings.xml

@@ -433,7 +433,7 @@
 
     <string name="tx_locked">Monto trabado hasta el bloque %1$d (faltan %2$d bloques ≈ %3$,.2f días)</string>
 
-    <string name="label_streetmode">Modo calle activado\nSólo se ºmostrarán transacciones nuevas</string>
+    <string name="label_streetmode">Modo calle activado\nSólo se mostrarán transacciones nuevas</string>
 
     <string name="pocketchange_info">To reduce waiting time on repeated spending, Monerujo can create spare change at the expense of higher fees. It\'ll try to create and maintain at least 6 coins of the selected amount.</string>
     <string name="pocketchange_create_title">Create Change</string>

app/src/main/res/values/arrays.xml

@@ -10,4 +10,46 @@
         <item>Oled</item>
     </string-array>
 
+    <string-array name="currency" translatable="false">
+        <item>EUR</item>
+        <item>USD</item>
+        <item>JPY</item>
+        <item>GBP</item>
+        <item>CHF</item>
+        <item>CAD</item>
+
+        <item>AUD</item>
+        <item>BGN</item>
+        <item>BRL</item>
+        <item>CNY</item>
+        <item>CZK</item>
+        <item>DKK</item>
+        <item>HKD</item>
+        <item>HUF</item>
+        <item>IDR</item>
+        <item>ILS</item>
+        <item>INR</item>
+        <item>ISK</item>
+        <item>KRW</item>
+        <item>MXN</item>
+        <item>MYR</item>
+        <item>NOK</item>
+        <item>NZD</item>
+        <item>PHP</item>
+        <item>PLN</item>
+        <item>RON</item>
+        <item>SEK</item>
+        <item>SGD</item>
+        <item>THB</item>
+        <item>TRY</item>
+        <item>ZAR</item>
+        <!-- shitcoins are marked with a zero width space at the end (U+200B) -->
+        <!-- this is a hack to avoid having different arrays, i.e. shitcoins have 4 charatcers -->
+        <item>ARS​</item>
+        <item>IRR​</item>
+        <item>LBP​</item>
+        <item>RUB​</item>
+        <item>VES​</item>
+    </string-array>
+
 </resources>

app/src/main/res/values/strings.xml

@@ -282,42 +282,6 @@
     <string name="delete_alert_yes">Yes, do that!</string>
     <string name="delete_alert_no">No thanks!</string>
 
-    <string-array name="currency" translatable="false">
-        <item>EUR</item>
-        <item>USD</item>
-        <item>JPY</item>
-        <item>GBP</item>
-        <item>CHF</item>
-        <item>CAD</item>
-
-        <item>AUD</item>
-        <item>BGN</item>
-        <item>BRL</item>
-        <item>CNY</item>
-        <item>CZK</item>
-        <item>DKK</item>
-        <item>HKD</item>
-        <item>HRK</item>
-        <item>HUF</item>
-        <item>IDR</item>
-        <item>ILS</item>
-        <item>INR</item>
-        <item>ISK</item>
-        <item>KRW</item>
-        <item>MXN</item>
-        <item>MYR</item>
-        <item>NOK</item>
-        <item>NZD</item>
-        <item>PHP</item>
-        <item>PLN</item>
-        <item>RON</item>
-        <item>SEK</item>
-        <item>SGD</item>
-        <item>THB</item>
-        <item>TRY</item>
-        <item>ZAR</item>
-    </string-array>
-
     <string name="fab_create_new">Create new wallet</string>
     <string name="fab_restore_viewonly">Restore view-only wallet</string>
     <string name="fab_restore_key">Restore wallet from private keys</string>

app/src/test/java/com/m2049r/xmrwallet/service/exchange/yadio/ExchangeRateTest.java

@@ -0,0 +1,263 @@
+/*
+ * Copyright (c) 2017-2023 m2049r et al.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.m2049r.xmrwallet.service.exchange.yadio;
+
+import static org.junit.Assert.assertEquals;
+
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeApi;
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeCallback;
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeException;
+import com.m2049r.xmrwallet.service.exchange.api.ExchangeRate;
+import com.m2049r.xmrwallet.util.NetCipherHelper;
+
+import net.jodah.concurrentunit.Waiter;
+
+import org.json.JSONException;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.Date;
+import java.util.concurrent.TimeoutException;
+
+import okhttp3.OkHttpClient;
+import okhttp3.mockwebserver.MockResponse;
+import okhttp3.mockwebserver.MockWebServer;
+import okhttp3.mockwebserver.RecordedRequest;
+
+
+public class ExchangeRateTest {
+
+    private MockWebServer mockWebServer;
+
+    private ExchangeApi exchangeApi;
+
+    private Waiter waiter;
+
+    @Mock
+    ExchangeCallback mockExchangeCallback;
+
+    @Before
+    public void setUp() throws Exception {
+        mockWebServer = new MockWebServer();
+        mockWebServer.start();
+
+        waiter = new Waiter();
+
+        MockitoAnnotations.initMocks(this);
+        NetCipherHelper.Request.mockClient = new OkHttpClient();
+        exchangeApi = new ExchangeApiImpl(mockWebServer.url("/"));
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        mockWebServer.shutdown();
+    }
+
+    @Test
+    public void queryExchangeRate_shouldBeGetMethod()
+            throws InterruptedException, TimeoutException {
+
+        exchangeApi.queryExchangeRate("EUR", "USD", mockExchangeCallback);
+
+        RecordedRequest request = mockWebServer.takeRequest();
+        assertEquals("GET", request.getMethod());
+    }
+
+    @Test
+    public void queryExchangeRate_shouldBeEUR()
+            throws InterruptedException, TimeoutException {
+
+        exchangeApi.queryExchangeRate("CHF", "USD", new ExchangeCallback() {
+            @Override
+            public void onSuccess(final ExchangeRate exchangeRate) {
+                waiter.fail();
+                waiter.resume();
+            }
+
+            @Override
+            public void onError(final Exception e) {
+                waiter.assertTrue(e instanceof IllegalArgumentException);
+                waiter.resume();
+            }
+
+        });
+        waiter.await();
+    }
+
+
+    @Test
+    public void queryExchangeRate_shouldBeOneForEur()
+            throws InterruptedException, TimeoutException {
+
+        exchangeApi.queryExchangeRate("EUR", "EUR", new ExchangeCallback() {
+            @Override
+            public void onSuccess(final ExchangeRate exchangeRate) {
+                waiter.assertEquals(1.0, exchangeRate.getRate());
+                waiter.resume();
+            }
+
+            @Override
+            public void onError(final Exception e) {
+                waiter.fail();
+                waiter.resume();
+            }
+
+        });
+        waiter.await();
+    }
+
+    @Test
+    public void queryExchangeRate_wasSuccessfulShouldRespondWithUsdRate()
+            throws InterruptedException, JSONException, TimeoutException {
+        final String base = "EUR";
+        final String quote = "USD";
+        final double rate = 1.1043;
+
+        MockResponse jsonMockResponse = new MockResponse().setBody(createMockExchangeRateResponse(quote, rate));
+        mockWebServer.enqueue(jsonMockResponse);
+
+        exchangeApi.queryExchangeRate(base, quote, new ExchangeCallback() {
+            @Override
+            public void onSuccess(final ExchangeRate exchangeRate) {
+                waiter.assertEquals(base, exchangeRate.getBaseCurrency());
+                waiter.assertEquals(quote, exchangeRate.getQuoteCurrency());
+                waiter.assertEquals(rate, exchangeRate.getRate());
+                waiter.resume();
+            }
+
+            @Override
+            public void onError(final Exception e) {
+                waiter.fail(e);
+                waiter.resume();
+            }
+        });
+        waiter.await();
+    }
+
+    @Test
+    public void queryExchangeRate_wasSuccessfulShouldRespondWithAudRate()
+            throws InterruptedException, JSONException, TimeoutException {
+        final String base = "EUR";
+        final String quote = "AUD";
+        final double rate = 99.114651;
+
+        MockResponse jsonMockResponse = new MockResponse().setBody(createMockExchangeRateResponse(quote, rate));
+        mockWebServer.enqueue(jsonMockResponse);
+
+        exchangeApi.queryExchangeRate(base, quote, new ExchangeCallback() {
+            @Override
+            public void onSuccess(final ExchangeRate exchangeRate) {
+                waiter.assertEquals(base, exchangeRate.getBaseCurrency());
+                waiter.assertEquals(quote, exchangeRate.getQuoteCurrency());
+                waiter.assertEquals(rate, exchangeRate.getRate());
+                waiter.resume();
+            }
+
+            @Override
+            public void onError(final Exception e) {
+                waiter.fail(e);
+                waiter.resume();
+            }
+        });
+        waiter.await();
+    }
+
+
+    @Test
+    public void queryExchangeRate_wasSuccessfulShouldRespondWithZarRate()
+            throws InterruptedException, JSONException, TimeoutException {
+        final String base = "EUR";
+        final String quote = "ZAR";
+        final double rate = 99.114651;
+
+        MockResponse jsonMockResponse = new MockResponse().setBody(createMockExchangeRateResponse(quote, rate));
+        mockWebServer.enqueue(jsonMockResponse);
+
+        exchangeApi.queryExchangeRate(base, quote, new ExchangeCallback() {
+            @Override
+            public void onSuccess(final ExchangeRate exchangeRate) {
+                waiter.assertEquals(base, exchangeRate.getBaseCurrency());
+                waiter.assertEquals(quote, exchangeRate.getQuoteCurrency());
+                waiter.assertEquals(rate, exchangeRate.getRate());
+                waiter.resume();
+            }
+
+            @Override
+            public void onError(final Exception e) {
+                waiter.fail(e);
+                waiter.resume();
+            }
+        });
+        waiter.await();
+    }
+
+    @Test
+    public void queryExchangeRate_wasNotSuccessfulShouldCallOnError()
+            throws InterruptedException, JSONException, TimeoutException {
+        mockWebServer.enqueue(new MockResponse().setResponseCode(500));
+        exchangeApi.queryExchangeRate("EUR", "USD", new ExchangeCallback() {
+            @Override
+            public void onSuccess(final ExchangeRate exchangeRate) {
+                waiter.fail();
+                waiter.resume();
+            }
+
+            @Override
+            public void onError(final Exception e) {
+                waiter.assertTrue(e instanceof ExchangeException);
+                waiter.assertTrue(((ExchangeException) e).getCode() == 500);
+                waiter.resume();
+            }
+
+        });
+        waiter.await();
+    }
+
+    @Test
+    public void queryExchangeRate_unknownAssetShouldCallOnError()
+            throws InterruptedException, JSONException, TimeoutException {
+        MockResponse jsonMockResponse = new MockResponse().setBody(createMockExchangeRateResponse("X", 0));
+        mockWebServer.enqueue(jsonMockResponse);
+        exchangeApi.queryExchangeRate("EUR", "ABC", new ExchangeCallback() {
+            @Override
+            public void onSuccess(final ExchangeRate exchangeRate) {
+                waiter.fail();
+                waiter.resume();
+            }
+
+            @Override
+            public void onError(final Exception e) {
+                waiter.assertTrue(e instanceof ExchangeException);
+                ExchangeException ex = (ExchangeException) e;
+                waiter.assertEquals(ex.getCode(), 200);
+                waiter.assertEquals(ex.getErrorMsg(), "currency not found");
+                waiter.resume();
+            }
+        });
+        waiter.await();
+    }
+
+    static public String createMockExchangeRateResponse(String quote, double rate) {
+        if (!quote.equals("X")) {
+            return "{\"request\":{\"amount\":1,\"from\":\"EUR\",\"to\":\"" + quote + "\"},\"result\":" + rate + ",\"rate\":" + rate + ",\"timestamp\":" + new Date().getTime() + "}";
+        }
+        return "{\"error\":\"currency not found\"}";
+    }
+}

build.gradle

@@ -5,7 +5,7 @@ buildscript {
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:8.1.0'
+        classpath 'com.android.tools.build:gradle:8.1.2'
     }
 }