solution: read upstream config from specified yaml

src/test/groovy/io/emeraldpay/dshackle/config/UpstreamsReaderSpec.groovy

@@ -0,0 +1,57 @@
+package io.emeraldpay.dshackle.config
+
+import spock.lang.Specification
+
+class UpstreamsReaderSpec extends Specification {
+
+    UpstreamsReader reader = new UpstreamsReader()
+
+    def "Parse standard config"() {
+        setup:
+        def config = this.class.getClassLoader().getResourceAsStream("upstreams-basic.yaml")
+        when:
+        def act = reader.read(config)
+        then:
+        act != null
+        act.version == "v1"
+        with(act.defaultOptions) {
+            size() == 1
+            with(get(0)) {
+                chains == ["ethereum"]
+                options.quorum == 1
+                options.minPeers == 3
+                options.disableSyncing
+            }
+        }
+        act.upstreams.size() == 2
+        with(act.upstreams.get(0)) {
+            id == "local"
+            chain == "ethereum"
+            provider == "geth"
+            endpoints.size() == 2
+            with(endpoints.get(0)) {
+                type == Upstreams.EndpointType.JSON_RPC
+                url == new URI("http://localhost:8545")
+            }
+            with(endpoints.get(1)) {
+                type == Upstreams.EndpointType.WEBSOCKET
+                url == new URI("ws://localhost:8546")
+            }
+        }
+        with(act.upstreams.get(1)) {
+            id == "infura"
+            chain == "ethereum"
+            provider == "infura"
+            endpoints.size() == 1
+            with(endpoints.get(0)) {
+                type == Upstreams.EndpointType.JSON_RPC
+                url == new URI("https://mainnet.infura.io/v3/fa28c968191849c1aff541ad1d8511f2")
+                auth instanceof Upstreams.BasicAuth
+                with((Upstreams.BasicAuth)auth) {
+                    key == "4fc258fe41a68149c199ad8f281f2015"
+                }
+            }
+
+        }
+    }
+}