added make targets for commenting line in go.mod

Makefile

@@ -198,6 +198,11 @@ integration-run-proxy: ## Runs the proxy interactive testing environment
 integration-run-ssh: ## Runs the ssh interactive testing environment
 	./integration/run-ssh-env.sh
 
+mod-comm: ## Comments the 'replace' rule in go.mod
+	./ci_scripts/go_mod_replace.sh comment go.mod
+
+mod-uncomm: ## Uncomments the 'replace' rule in go.mod
+	./ci_scripts/go_mod_replace.sh uncomment go.mod
+
 help:
 	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
-

ci_scripts/go_mod_replace.sh

@@ -0,0 +1,34 @@
+#!/usr/bin/env bash
+
+if [[ $# -ne 2 ]]; then
+    exit 0
+fi
+
+# Inputs.
+action=$1
+filename=$2
+
+# Line to comment/uncomment in go.mod
+line="replace github.com\/skycoin\/dmsg => ..\/dmsg"
+
+function print_usage() {
+    echo $"Usage: $0 (comment|uncomment) <filename>"
+}
+
+case "$action" in
+    comment)
+        echo "commenting ${filename}..."
+        sed -i -e "/$line/s/^\/*/\/\//" ${filename}
+        ;;
+    uncomment)
+        echo "uncommenting ${filename}..."
+        sed -i -e "/$line/s/^\/\/*//" ${filename}
+        ;;
+    help)
+        print_usage
+        ;;
+    *)
+        print_usage
+        exit 1
+        ;;
+esac

go.mod

@@ -29,3 +29,6 @@ require (
 	golang.org/x/text v0.3.2 // indirect
 	golang.org/x/tools v0.0.0-20190627033414-4874f863e654 // indirect
 )
+
+// Uncomment for tests with alternate branches of 'dmsg'
+//replace github.com/skycoin/dmsg => ../dmsg