[wasmtime-api] run examples as tests (#466)

* [wasmtime-api] run example as tests

* Update wasmtime-api/tests/examples.rs

Co-Authored-By: Nick Fitzgerald <fitzgen@gmail.com>

* disable multi example test on windows

wasmtime-api/tests/examples.rs

@@ -0,0 +1,39 @@
+use std::env;
+use std::process::{Command, Stdio};
+
+fn run_example(name: &'static str) {
+    let cargo = env::var("CARGO").unwrap_or("cargo".to_string());
+    let pkg_dir = env!("CARGO_MANIFEST_DIR");
+    assert!(
+        Command::new(cargo)
+            .current_dir(pkg_dir)
+            .stdout(Stdio::null())
+            .args(&["run", "-q", "--example", name])
+            .status()
+            .expect("success")
+            .success(),
+        "failed to execute the example '{}'",
+        name,
+    );
+}
+
+#[test]
+fn test_run_hello_example() {
+    run_example("hello");
+}
+
+#[test]
+fn test_run_gcd_example() {
+    run_example("gcd");
+}
+
+#[test]
+fn test_run_memory_example() {
+    run_example("memory");
+}
+
+#[cfg(not(target_os = "windows"))]
+#[test]
+fn test_run_multi_example() {
+    run_example("multi");
+}