solution: newHeads subsription

src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/subscribe/ConnectNewHeadsSpec.groovy

@@ -0,0 +1,34 @@
+package io.emeraldpay.dshackle.upstream.ethereum.subscribe
+
+import io.emeraldpay.dshackle.test.TestingCommons
+import io.emeraldpay.dshackle.upstream.Head
+import io.emeraldpay.dshackle.upstream.ethereum.EthereumMultistream
+import reactor.core.publisher.Flux
+import reactor.test.StepVerifier
+import spock.lang.Specification
+
+class ConnectNewHeadsSpec extends Specification {
+
+    def "Reuse same head"() {
+        setup:
+        def head = Mock(Head) {
+            1 * getFlux() >> Flux.fromIterable([
+                    TestingCommons.blockForEthereum(100)
+            ])
+        }
+        def up = Mock(EthereumMultistream) {
+            1 * getHead() >> head
+        }
+        ConnectNewHeads connectNewHeads = new ConnectNewHeads(up)
+        when:
+        def act1 = connectNewHeads.connect()
+        def act2 = connectNewHeads.connect()
+        then:
+        StepVerifier.create(act1)
+                .expectNextCount(1)
+                .expectComplete()
+        StepVerifier.create(act2)
+                .expectNextCount(1)
+                .expectComplete()
+    }
+}

src/test/groovy/io/emeraldpay/dshackle/upstream/ethereum/subscribe/json/NewHeadSpec.groovy

@@ -0,0 +1,46 @@
+package io.emeraldpay.dshackle.upstream.ethereum.subscribe.json
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import io.emeraldpay.dshackle.Global
+import io.emeraldpay.etherjar.domain.Address
+import io.emeraldpay.etherjar.domain.BlockHash
+import io.emeraldpay.etherjar.domain.Bloom
+import spock.lang.Specification
+
+import java.time.Instant
+
+class NewHeadSpec extends Specification {
+
+    def "Serialize to a correct JSON"() {
+        setup:
+        NewHead obj = new NewHead(
+                0xc7f3b4,
+                BlockHash.from("0xd3b7ae1a79f5418debae9b8e9318094298c087183be0f7a0151b0e76ba38d6bc"),
+                BlockHash.from("0xcda7fd1d6ee2d5da7505a0634e27f41d5ae87a344cd75bb64c1dc0863fbe9c0a"),
+                Instant.ofEpochSecond(0x6128264d),
+                new BigInteger("1de7f7a458cc08", 16),
+                0x1ca35ef,
+                0x7bb33e,
+                Bloom.from("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"),
+                Address.from("0x829bd824b016326a401d083b33d092293333a830"),
+                null
+        )
+        ObjectMapper objectMapper = Global.getObjectMapper()
+        def exp = '{' +
+                '"number":"0xc7f3b4",' +
+                '"hash":"0xd3b7ae1a79f5418debae9b8e9318094298c087183be0f7a0151b0e76ba38d6bc",' +
+                '"parentHash":"0xcda7fd1d6ee2d5da7505a0634e27f41d5ae87a344cd75bb64c1dc0863fbe9c0a",' +
+                '"timestamp":"0x6128264d",' +
+                '"difficulty":"0x1de7f7a458cc08",' +
+                '"gasLimit":"0x1ca35ef",' +
+                '"gasUsed":"0x7bb33e",' +
+                '"logsBloom":"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",' +
+                '"miner":"0x829bd824b016326a401d083b33d092293333a830"' +
+                '}'
+        when:
+        def json = objectMapper.writeValueAsString(obj)
+
+        then:
+        json == exp
+    }
+}