Travis: remove test.sh, improve travis file

.travis.yml

@@ -1,16 +1,16 @@
 language: go
-sudo: false
 go:
-  - 1.11
+  - tip
+  - 1.12.x
+  - 1.11.x
   - 1.10.x
-  - 1.9
-  - 1.8
-
-before_install:
-  - go get -u -t ./...
 
 script:
-  - GO111MODULE=on ./test.sh
+  - go test -race -coverprofile=coverage.txt -covermode=atomic ./...
 
 after_success:
   - bash <(curl -s https://codecov.io/bash)
+
+matrix:
+  allow_failures:
+    - go: tip

test.sh

@@ -1,12 +0,0 @@
-#!/usr/bin/env bash
-
-set -e
-echo "" > coverage.txt
-
-for d in $(go list ./... | grep -v vendor); do
-    go test -v -race -coverprofile=profile.out -covermode=atomic $d
-    if [ -f profile.out ]; then
-        cat profile.out >> coverage.txt
-        rm profile.out
-    fi
-done