# Test Request <1>

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The [Test Request `<1>`](https://www.onixs.biz/fix-dictionary/4.4/msgType_1_1.html) message forces a heartbeat from the opposing application. The [Test Request `<1>`](https://www.onixs.biz/fix-dictionary/4.4/msgType_1_1.html) message checks sequence numbers or verifies communication line status. The opposite application responds to the [Test Request `<1>`](https://www.onixs.biz/fix-dictionary/4.4/msgType_1_1.html) with a [Heartbeat `<0>`](https://www.onixs.biz/fix-dictionary/4.4/msgType_0_0.html) containing the [TestReqID `<112>`](https://www.onixs.biz/fix-dictionary/4.4/tagNum_112.html).

The [TestReqID `<112>`](https://www.onixs.biz/fix-dictionary/4.4/tagNum_112.html) verifies that the opposite application is generating the heartbeat as the result of [Test Request `<1>`](https://www.onixs.biz/fix-dictionary/4.4/msgType_1_1.html) and not a normal timeout. The opposite application includes the [TestReqID `<112>`](https://www.onixs.biz/fix-dictionary/4.4/tagNum_112.html) in the resulting [Heartbeat `<0>`](https://www.onixs.biz/fix-dictionary/4.4/msgType_0_0.html). Any string can be used as the [TestReqID `<112>`](https://www.onixs.biz/fix-dictionary/4.4/tagNum_112.html) (one suggestion is to use a timestamp string).

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### FIELDS

| Tag | Name                                                                  | Req | Description                                                                                                                                                                                                             |
| --- | --------------------------------------------------------------------- | --- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
|     | [Standard Header](/trading/fix/overview/standard-header)                      | Y   | [MsgType](https://www.onixs.biz/fix-dictionary/4.4/msgs_by_msg_type.html) = `1`                                                                                                                                         |
| 112 | [TestReqID](https://www.onixs.biz/fix-dictionary/4.4/tagNum_112.html) | Y   | Identifier included in [Test Request `<1>`](https://www.onixs.biz/fix-dictionary/4.4/msgType_1_1.html) message to be returned in resulting [Heartbeat `<0>`](https://www.onixs.biz/fix-dictionary/4.4/msgType_0_0.html) |
|     | [Standard Trailer](/trading/fix/overview/standard-trailer)                    | Y   |                                                                                                                                                                                                                         |