如何模拟 Android NFC Tag 对象以进行单元测试

问题描述

我目前正在开发一个需要 NFC 集成的 Android 项目.现在我想编写一些 (j) 单元测试来查看应用程序是否可以接收 NFC 意图(特别是 ACTION_TECH_DISCOVERED)并将给定的标签(在 NfcAdapter.EXTRA_TAG 中)放在总线系统.但是令我惊讶的是，我无法创建 Tag 实例或模拟实例.有人可以向我解释我如何(单元)测试吗?

I'm currently working on an Android project which needs NFC integration. Now I want to write some (j)unit tests to see if the application can receive NFC intents (specifically ACTION_TECH_DISCOVERED) and put the given tag (in NfcAdapter.EXTRA_TAG) on a bus system. However to my surprise I cannot create a Tag instance or mock one. Can someone explain to me how I can (unit) test?

此时我什至会接受某种形式的集成测试，即:

At this point I would even accept a form of integration testing, the process of:

1. 检测 NFC 意图
2. 获取 Tag 对象
3. 把它放在包裹在CardDetectedEvent中的总线上.

1. Detect the NFC Intent
2. Get the Tag object
3. Put it on the bus wrapped in a CardDetectedEvent.

我有一部启用 NFC 的手机和几张用于测试的卡.

I have a phone with NFC enabled and a few cards for testing.

Android SDK 版本:19
使用的库:robolectric、junit 和 mockito

Android SDK version: 19
Libraries used: robolectric, junit and mockito

推荐答案

可以使用反射创建一个模拟标签对象实例(注意这不是公共 Android SDK 的一部分，因此在未来的 Android 版本中可能会失败).

It's possible to create a mock tag object instance using reflection (note that this is not part of the public Android SDK, so it might fail for future Android versions).

1. 通过反射获取createMockTag()方法:

Class tagClass = Tag.class;
Method createMockTagMethod = tagClass.getMethod("createMockTag", byte[].class, int[].class, Bundle[].class);

定义一些常量来准备模拟标签实例:

Define some constants for preparing the mock tag instance:

final int TECH_NFC_A = 1;
final String EXTRA_NFC_A_SAK = "sak";    // short (SAK byte value)
final String EXTRA_NFC_A_ATQA = "atqa";  // byte[2] (ATQA value)

final int TECH_NFC_B = 2;
final String EXTRA_NFC_B_APPDATA = "appdata";    // byte[] (Application Data bytes from ATQB/SENSB_RES)
final String EXTRA_NFC_B_PROTINFO = "protinfo";  // byte[] (Protocol Info bytes from ATQB/SENSB_RES)

final int TECH_ISO_DEP = 3;
final String EXTRA_ISO_DEP_HI_LAYER_RESP = "hiresp";  // byte[] (null for NfcA)
final String EXTRA_ISO_DEP_HIST_BYTES = "histbytes";  // byte[] (null for NfcB)

final int TECH_NFC_F = 4;
final String EXTRA_NFC_F_SC = "systemcode";  // byte[] (system code)
final String EXTRA_NFC_F_PMM = "pmm";        // byte[] (manufacturer bytes)

final int TECH_NFC_V = 5;
final String EXTRA_NFC_V_RESP_FLAGS = "respflags";  // byte (Response Flag)
final String EXTRA_NFC_V_DSFID = "dsfid";           // byte (DSF ID)

final int TECH_NDEF = 6;
final String EXTRA_NDEF_MSG = "ndefmsg";              // NdefMessage (Parcelable)
final String EXTRA_NDEF_MAXLENGTH = "ndefmaxlength";  // int (result for getMaxSize())
final String EXTRA_NDEF_CARDSTATE = "ndefcardstate";  // int (1: read-only, 2: read/write, 3: unknown)
final String EXTRA_NDEF_TYPE = "ndeftype";            // int (1: T1T, 2: T2T, 3: T3T, 4: T4T, 101: MF Classic, 102: ICODE)

final int TECH_NDEF_FORMATABLE = 7;

final int TECH_MIFARE_CLASSIC = 8;

final int TECH_MIFARE_ULTRALIGHT = 9;
final String EXTRA_MIFARE_ULTRALIGHT_IS_UL_C = "isulc";  // boolean (true: Ultralight C)

final int TECH_NFC_BARCODE = 10;
final String EXTRA_NFC_BARCODE_BARCODE_TYPE = "barcodetype";  // int (1: Kovio/ThinFilm)

为您的标签类型创建技术附加包.例如，对于带有 NDEF 消息的 NFC-A 标签:

Create the tech-extras bundle for your tag type. For instance, for an NFC-A tag with an NDEF message:

Bundle nfcaBundle = new Bundle();
nfcaBundle.putByteArray(EXTRA_NFC_A_ATQA, new byte[]{ (byte)0x44, (byte)0x00 }); //ATQA for Type 2 tag
nfcaBundle.putShort(EXTRA_NFC_A_SAK , (short)0x00); //SAK for Type 2 tag

Bundle ndefBundle = new Bundle();
ndefBundle.putInt(EXTRA_NDEF_MAXLENGTH, 48); // maximum message length: 48 bytes
ndefBundle.putInt(EXTRA_NDEF_CARDSTATE, 1); // read-only
ndefBundle.putInt(EXTRA_NDEF_TYPE, 2); // Type 2 tag
NdefMessage myNdefMessage = ...; // create an NDEF message
ndefBundle.putParcelable(EXTRA_NDEF_MSG, myNdefMessage);  // add an NDEF message

为您的标签准备一个防冲突标识符/UID(参见 Tag.getId() 方法).例如.类型 2 标记的 7 字节 UID:

Prepare an anti-collision identifier/UID for your tag (see Tag.getId() method). E.g. a 7-byte-UID for a Type 2 tag:

byte[] tagId = new byte[] { (byte)0x3F, (byte)0x12, (byte)0x34, (byte)0x56, (byte)0x78, (byte)0x90, (byte)0xAB };

然后就可以通过调用createMockTag()方法来创建一个mock标签实例

Then you can create a mock tag instance by invoking the createMockTag() method

Tag mockTag = (Tag)createMockTagMethod.invoke(null,
        tagId,                                     // tag UID/anti-collision identifier (see Tag.getId() method)
        new int[] { TECH_NFC_A, TECH_NDEF },       // tech-list
        new Bundle[] { nfcaBundle, ndefBundle });  // array of tech-extra bundles, each entry maps to an entry in the tech-list

创建该模拟标签对象后，您可以将其作为 NFC 发现意图的一部分发送.例如.对于 TECH_DISCOVERED 意图:

Once you created that mock tag object, you can send it as part of an NFC discovery intent. E.g. for a TECH_DISCOVERED intent:

Intent techIntent = new Intent(NfcAdapter.ACTION_TECH_DISCOVERED);
techIntent.putExtra(NfcAdapter.EXTRA_ID, tagId);
techIntent.putExtra(NfcAdapter.EXTRA_TAG, mockTag);
techIntent.putExtra(NfcAdapter.EXTRA_NDEF_MESSAGES, new NdefMessage[]{ myNdefMessage });  // optionally add an NDEF message

然后您可以将此意图发送到您的活动:

You can then send this intent to your activity:

techIntent.setComponent(...); // or equivalent to optionally set an explicit receiver
startActivity(techIntent);

接收者甚至可以使用模拟标签对象来检索技术类的实例.但是，任何需要 IO 操作的方法都会失败.

The receiver can even use the mock tag object to retrieve instances of the technology classes. However, any method that requires IO operations will fail.

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