test: Add a smoke test

Author: kateinoigakukun

test/test_build_smoke.rb

@@ -0,0 +1,40 @@
+require "test-unit"
+require "tmpdir"
+require "bundler"
+
+class TestBuildSmoke < Test::Unit::TestCase
+  def run_rbwasm(*args)
+    rbwasm_path = File.expand_path("../../exe/rbwasm", __FILE__)
+    system("bundle", "exec", rbwasm_path, *args, exception: true)
+  end
+
+  def run_wasmtime(*args)
+    IO.popen(["wasmtime", *args], &:read)
+  end
+
+  def test_build_rack
+    Dir.mktmpdir do |dir|
+      gemfile_path = File.join(dir, "Gemfile")
+      output_path = File.join(dir, "output.wasm")
+
+      File.write(gemfile_path, <<-GEMFILE)
+      source "https://rubygems.org"
+      gem "rack", "3.0.8"
+      GEMFILE
+      Bundler.with_unbundled_env do
+        ENV["RUBY_WASM_ROOT"] = File.expand_path("../../", __FILE__)
+        ENV["BUNDLE_GEMFILE"] = gemfile_path
+        assert system("bundle", "install")
+        run_rbwasm("build", "-o", output_path)
+        assert_equal "Rack::RELEASE=3.0.8\n",
+                     run_wasmtime(
+                       output_path,
+                       "-r/bundle/setup.rb",
+                       "-rrack",
+                       "-e",
+                       "puts \"Rack::RELEASE=\#{Rack::RELEASE}\""
+                     )
+      end
+    end
+  end
+end