[csharp] update travis for dotnet

.travis.yml

@@ -1,3 +1,4 @@
+dist: trusty
 sudo: true
 
 language: java
@@ -45,6 +46,9 @@ matrix:
     - os: linux
       jdk: oraclejdk7
       env: TARGET=csharp
+    - os: linux
+      jdk: oraclejdk7
+      env: TARGET=dotnet
     - os: linux
       jdk: oraclejdk7
       env: TARGET=python2
@@ -59,6 +63,7 @@ matrix:
       env: TARGET=go
 
 before_install:
+  - ./.travis/before-install-mvn3.3.9-trusty.sh
   - ./.travis/before-install-$TRAVIS_OS_NAME-$TARGET.sh
 
 script:

.travis/before-install-linux-dotnet.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+set -euo pipefail
+
+sudo sh -c 'echo "deb [arch=amd64] https://apt-mo.trafficmanager.net/repos/dotnet-release/ trusty main" > /etc/apt/sources.list.d/dotnetdev.list'
+sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 417A0893
+sudo apt-get update
+
+sudo apt-get install dotnet-dev-1.0.0-preview2.1-003177
+

.travis/before-install-mvn3.3.9-trusty.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+set -ex
+
+wget http://apache.mirrors.lucidnetworks.net/maven/maven-3/3.3.9/binaries/apache-maven-3.3.9-bin.tar.gz && \
+    wget https://www.apache.org/dist/maven/maven-3/3.3.9/binaries/apache-maven-3.3.9-bin.tar.gz.md5 && \
+    echo "$(cat apache-maven-3.3.9-bin.tar.gz.md5)  apache-maven-3.3.9-bin.tar.gz" > apache-maven-3.3.9-bin.tar.gz.md5 && \
+    md5sum -c *.md5
+
+sudo rm -rf /usr/local/maven/ && sudo mkdir -p /usr/local/maven && \
+    sudo tar xzvf apache-maven-3.3.9-bin.tar.gz -C /usr/local/maven --strip-components=1
+
+mvn -v
+

.travis/run-tests-dotnet.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+mvn -q -Dparallel=methods -DthreadCount=4 -Dtest=csharp.* -DargLine="-Dantlr-csharp-netstandard=true" test
+