Refactor test code into python (#264)

Keep the basic workflow test (checking what a user would do to get started) in bash, but otherwise it's more convenient for most tests to be in python.

test.py

@@ -0,0 +1,55 @@
+import os
+import subprocess
+
+# Utilities
+
+def check_call(cmd):
+  subprocess.check_call(cmd.split(' '))
+
+# Set up
+
+open('hello_world.cpp', 'w').write('int main() {}')
+
+# Tests
+
+print('update')
+check_call('./emsdk update-tags')
+
+print('test latest')
+assert 'fastcomp' in open(os.path.expanduser('~/.emscripten')).read()
+assert 'upstream' not in open(os.path.expanduser('~/.emscripten')).read()
+
+print('test latest-releases-upstream')
+check_call('python2 ./emsdk install latest-upstream')
+check_call('./emsdk activate latest-upstream')
+check_call('upstream/emscripten/emcc hello_world.cpp')
+assert open(os.path.expanduser('~/.emscripten')).read().count('LLVM_ROOT') == 1
+assert 'upstream' in open(os.path.expanduser('~/.emscripten')).read()
+assert 'fastcomp' not in open(os.path.expanduser('~/.emscripten')).read()
+
+print('test tot-upstream')
+check_call('./emsdk install tot-upstream')
+check_call('./emsdk activate tot-upstream')
+check_call('upstream/emscripten/emcc hello_world.cpp')
+
+print('test tot-fastcomp')
+check_call('./emsdk install tot-fastcomp')
+check_call('./emsdk activate tot-fastcomp')
+check_call('fastcomp/emscripten/emcc hello_world.cpp')
+
+print('test specific release (old)')
+check_call('./emsdk install sdk-1.38.31-64bit')
+check_call('./emsdk activate tot-fastcomp')
+
+print('test specific release (new, short name)')
+check_call('./emsdk install 1.38.33')
+check_call('./emsdk activate tot-fastcomp')
+assert 'fastcomp' in open(os.path.expanduser('~/.emscripten')).read()
+assert 'upstream' not in open(os.path.expanduser('~/.emscripten')).read()
+
+print('test specific release (new, full name)')
+check_call('./emsdk install sdk-1.38.33-upstream-64bit')
+check_call('./emsdk activate sdk-1.38.33-upstream-64bit')
+
+print('test binaryen source build')
+check_call('./emsdk install --build=Release binaryen-master-64bit')