Test node health in full_client_test.go (cosmos#1290)

closes: cosmos#1258 

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

Tests:
- Introduced a new test, `TestHealth`, to ensure the proper functioning
of the `Health` function in our node application. This test sets up a
mock application, starts the RPC server, and calls the `Health`
function. It asserts that the returned error is nil and the result is
empty. This addition enhances the overall quality and reliability of our
system.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

node/full_client_test.go

@@ -1191,3 +1191,24 @@ func TestFutureGenesisTime(t *testing.T) {
 
 	assert.True(beginBlockTime.After(genesisTime))
 }
+
+func TestHealth(t *testing.T) {
+	assert := assert.New(t)
+	require := require.New(t)
+
+	mockApp, rpc := getRPC(t)
+	mockApp.On("BeginBlock", mock.Anything).Return(abci.ResponseBeginBlock{})
+	mockApp.On("CheckTx", mock.Anything).Return(abci.ResponseCheckTx{})
+	mockApp.On("EndBlock", mock.Anything).Return(abci.ResponseEndBlock{})
+	mockApp.On("Commit", mock.Anything).Return(abci.ResponseCommit{})
+
+	err := rpc.node.Start()
+	require.NoError(err)
+	defer func() {
+		require.NoError(rpc.node.Stop())
+	}()
+
+	resultHealth, err := rpc.Health(context.Background())
+	assert.Nil(err)
+	assert.Empty(resultHealth)
+}