Install protoc and gencodec

mockgen is installed as part of go get -t ./... (which pulls in gomock).

.travis.yml

@@ -23,6 +23,9 @@ install:
   - go get -u golang.org/x/lint/golint
   - go get -u golang.org/x/tools/cmd/goimports
   - go get gopkg.in/check.v1
+  - go get github.com/harmony-ek/gencodec
+  - go get github.com/golang/protobuf/protoc-gen-go
+  - ./scripts/install_protoc.sh -V 3.6.1
   - ./scripts/travis_checker.sh
   - go build -v ./...
 script:

scripts/install_protoc.sh

@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+set -eu
+unset -v opt OPTIND OPTARG version platform destdir
+version=
+platform=
+destdir=/usr/local
+while getopts :V:P:d: opt
+do
+	case "${opt}" in
+	V) version="${OPTARG}";;
+	P) platform="${OPTARG}";;
+	d) destdir="${OPTARG}";;
+	"?") echo "unrecognized option -${OPTARG}" >&2; exit 64;;
+	":") echo "missing argument for -${OPTARG}" >&2; exit 64;;
+	*) echo "unhandled option -${OPTARG}" >&2; exit 70;;
+	esac
+done
+shift $((${OPTIND} - 1))
+case "${version}" in
+"") echo "protobuf version (-V) not specified" >&2; exit 64;;
+esac
+case "${platform}" in
+"")
+	platform=$(uname -s)
+	case "${platform}" in
+	Darwin) platform=osx;;
+	Linux) platform=linux;;
+	*) echo "unsupported OS name (${platform})" >&2; exit 69;;
+	esac
+	platform="${platform}-$(uname -m)"
+	;;
+esac
+unset -v tmpdir
+trap 'case "${tmpdir-}" in ?*) rm -rf "${tmpdir}";; esac' EXIT
+tmpdir=$(mktemp -d)
+cd "${tmpdir}"
+unset -v filename url
+filename="protoc-${version}-${platform}.zip"
+url="https://github.com/protocolbuffers/protobuf/releases/download/v${version}/${filename}"
+echo "Downloading protoc v${version} for ${platform}..."
+curl -s -S -L -o "${filename}" "${url}"
+echo "Downloaded as ${filename}; unzipping into ${destdir}..."
+sudo unzip -o -d "${destdir}" "${filename}"
+echo "protoc v${version} has been installed in ${destdir}."
+exit 0