Add non-reg tests for Nexus proxies

Ensure everything work fine again with those (things went bad at
1.0.0-RC1, because of the use of directory listings, that may not be
exhaustive in proxies - or may be just empty, e.g. currently with nexus 3)

scripts/launch-proxies.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+set -e
+
+MAX_WAIT=120
+
+wait_for() {
+  TARGET="$1"
+  I=0
+  while ! curl "$TARGET"; do
+    if [ "$I" -gt "$MAX_WAIT" ]; then
+      echo "$TARGET not available after $MAX_WAIT seconds" 1>&2
+      exit 1
+    fi
+
+    I="$(( $I + 1 ))"
+    sleep 1
+  done
+}
+
+docker run -d -p 9081:8081 --name nexus sonatype/nexus:2.14.4
+wait_for "http://localhost:9081/nexus/content/repositories/central/"
+
+docker run -d -p 9082:8081 --name nexus3 sonatype/nexus3:3.3.1
+wait_for "http://localhost:9082/repository/maven-central/"

scripts/travis.sh

@@ -24,6 +24,10 @@ launchTestRepo() {
   ./scripts/launch-test-repo.sh "$@"
 }
 
+launchProxyRepos() {
+  ./scripts/launch-proxies.sh
+}
+
 integrationTestsRequirements() {
   # Required for ~/.ivy2/local repo tests
   sbt ++2.11.11 coreJVM/publishLocal
@@ -217,6 +221,9 @@ else
       runSbtShadingTests
     fi
   else
+    # Required for the proxy tests (currently CentralNexus2ProxyTests and CentralNexus3ProxyTests)
+    launchProxyRepos
+
     runJvmTests
 
     testBootstrap