Add a Travis install script

Author: Lukasa

.travis.yml

@@ -42,9 +42,10 @@ matrix:
     - python: "3.7"
       dist: xenial
       env: TOXENV=packaging
+    - python: "3.6"
+      env: TOXENV=h2spec
 
 install:
-  - "pip install -U pip setuptools"
-  - "pip install -U tox"
+  - _travis/install.sh
 script:
   - tox -- --hypothesis-profile travis

_travis/install.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+set -e
+set -x
+
+pip install -U pip setuptools
+pip install -U tox
+
+if [ $TOXENV = "h2spec" ]; then
+    # We want to get the latest release of h2spec. We do that by asking the
+    # Github API for it, and then parsing the JSON for the appropriate kind of
+    # binary. Happily, the binary is always called "h2spec" so we don't need
+    # even more shenanigans to get this to work.
+    TARBALL=$(curl -s https://api.github.com/repos/summerwind/h2spec/releases/latest | jq '.assets[] | .browser_download_url | select(endswith("linux_amd64.tar.gz"))')
+    curl -LO "$TARBALL"
+    tar xvf $TARBALL
+    mv h2spec /usr/local/bin
+fi