[Qt] add payment request unit test for non matching networks

- verify that payment request network matches client network
- add static verifyNetwork() function to PaymentServer to be able to use
  the same validation code in GUI and unit-testing code

src/qt/test/paymentrequestdata.h

@@ -337,3 +337,27 @@ ssymvca1S/1KeM3n8Ydi2fi1JUzAAr59xPvNJRUeqCLP9upHn5z7br3P12Oz9A20\
 5/4wL4ClPRPVnOHgij0bEg+y0tGESqmF1rfOfXDszlo2U92wCxS07kq79YAZJ1Zo\
 XYh860/Q4wvc7lfiTe+dXBzPKAKhMy91yETY\
 ";
+
+//
+// Contains a testnet paytoaddress, so payment request network doesn't match client network
+//
+const char* paymentrequest1_cert2_BASE64 =
+"\
+Egt4NTA5K3NoYTI1NhrQBArNBDCCAkkwggExoAMCAQICAQEwDQYJKoZIhvcNAQEL\
+BQAwITEfMB0GA1UEAwwWUGF5bWVudFJlcXVlc3QgVGVzdCBDQTAeFw0xNTAxMTEx\
+ODIxMDhaFw0yNTAxMDgxODIxMDhaMCExHzAdBgNVBAMMFlBheW1lbnRSZXF1ZXN0\
+IFRlc3QgQ0EwgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBAMsZqzkzeBGo+i2N\
+mUak3Ciodr1V7S062VOy7N0OQYNDQHYkgDFAUET7cEb5VJaHPv5m3ppTBpU9xBcf\
+wbHHUt4VjA+mhRmYrl1khjvZM+X8kEqvWn20BtcM9R6r0yIYec8UERDDHBleL/P8\
+RkxEnVLjYTV9zigCXfMsgYb3EQShAgMBAAGjEDAOMAwGA1UdEwQFMAMBAf8wDQYJ\
+KoZIhvcNAQELBQADggEBABUJpl3QCqsoDSxAsQdV6zKT4VGV76AzoGj7etQsQY+r\
++S26VfWh/fMobEzuxFChr0USgLJ6FoK78hAtoZvt1lrye9yqFv/ig3WLWsJKWHHb\
+3RT6oR03CIwZXFSUasi08QDVLxafwsU5OMcPLucF3a1lRL1ccYrNgVCCx1+X7Bos\
+tIgDGRQQ4AyoHTcfVd2hEGeUv7k14mOxFsAp6851yosHq9Q2kwmdH+rHEJbjof87\
+yyKLagc4owyXBZYkQmkeHWCNqnuRmO5vUsfVb0UUrkD64o7Th/NjwooA7SCiUXl6\
+dfygT1b7ggpx7GC+sP2DsIM47IAZ55drjqX5u2f+Ba0iPQoEdGVzdBIhCIDWwowE\
+Ehl2qRQErGqUUwSsaMpDvWIaGnJGNQqi8oisGNeMy6UFKgxKdXN0IFRlc3Rpbmcq\
+gAFwThsozZxkZxzCn4R8WxNiLFV6m0ye9fEtSbolfaW+EjBMpO03lr/dwNnrclhg\
+ew+A05xfZztrAt16XKEY7qKJ/eY2nLd0fVAIu/nIt+7/VYVXT83zLrWc150aRS7W\
+AdJbL3JOJLs6Eyp5zrPbfI8faRttFAdONKDrJgIpuW1E3g==\
+";

src/qt/test/paymentservertests.cpp

@@ -115,6 +115,34 @@ void PaymentServerTests::paymentServerTests()
     r.paymentRequest.getMerchant(caStore, merchant);
     QCOMPARE(merchant, QString(""));
 
+    // Load second root certificate
+    caStore = X509_STORE_new();
+    X509_STORE_add_cert(caStore, parse_b64der_cert(caCert2_BASE64));
+    PaymentServer::LoadRootCAs(caStore);
+
+    QByteArray byteArray;
+
+    // For the tests below we just need the payment request data from
+    // paymentrequestdata.h parsed + stored in r.paymentRequest.
+    //
+    // These tests require us to bypass the following normal client execution flow
+    // shown below to be able to explicitly just trigger a certain condition!
+    //
+    // handleRequest()
+    // -> PaymentServer::eventFilter()
+    //   -> PaymentServer::handleURIOrFile()
+    //     -> PaymentServer::readPaymentRequestFromFile()
+    //       -> PaymentServer::processPaymentRequest()
+
+    // Contains a testnet paytoaddress, so payment request network doesn't match client network:
+    data = DecodeBase64(paymentrequest1_cert2_BASE64);
+    byteArray = QByteArray((const char*)&data[0], data.size());
+    r.paymentRequest.parse(byteArray);
+    // Ensure the request is initialized, because network "main" is default, even for
+    // uninizialized payment requests and that will fail our test here.
+    QVERIFY(r.paymentRequest.IsInitialized());
+    QCOMPARE(PaymentServer::verifyNetwork(r.paymentRequest.getDetails()), false);
+
     // Just get some random data big enough to trigger BIP70 DoS protection
     unsigned char randData[BIP70_MAX_PAYMENTREQUEST_SIZE + 1];
     GetRandBytes(randData, sizeof(randData));