Add integration tests.

Cargo.toml

@@ -17,4 +17,6 @@ env_logger = "0.8.3"
 wat = "1.0.37"
 
 [workspace]
-members = []
+members = [
+    "crates/test-modules"
+]

README.md

@@ -24,56 +24,74 @@ $ cargo run
 
 ## Testing
 
-To run tests:
+To run tests, first install the `wasm32-wasi` target:
+
+```text
+$ rustup target install wasm32-wasi
+```
+
+With the target installed, run the tests:
 
 ```text
 $ cargo test --all
 ```
 
 ## Demo
 
+### Prerequisites
+
 The demo requires [cargo-wasi](https://github.com/bytecodealliance/cargo-wasi), so install it using `cargo`:
 
 ```text
 $ cargo install cargo-wasi
 ```
 
-First, build the `markdown` module:
+### Building the `markdown` module
+
+The `markdown` module exposes an interface consisting of a `render` function that takes a string (the [Markdown](https://en.wikipedia.org/wiki/Markdown)) as an argument and returns a string (the rendered HTML).
+
+To build the `markdown` module:
 
 ```text
 $ cd demo/markdown
 $ cargo wasi build
 $ cp markdown.witx target/wasm32-wasi/debug/markdown.witx
 ```
 
-This module exposes an interface consisting of a `render` function that takes a string (the [Markdown](https://en.wikipedia.org/wiki/Markdown)) as an argument and returns a string (the rendered HTML).
-
 _Note: the linker currently expects either an embedded witx file in a custom section of the module or a witx file of the same name next to the input wasm module, so we copy the witx file to the target directory above._
 
-Next, build the `renderer` module:
+### Building the `renderer` module
+
+The `renderer` module will read input via `stdin`, pass the input as a string to the `render` function from the `markdown` module, and then print the returned HTML to `stdout`.
+
+To build the `renderer` module:
 
 ```text
 $ cd demo/renderer
 $ cargo wasi build
 ```
 
-This module will read input via `stdin`, pass the input as a string to the `render` function from the `markdown` module, and then print the returned HTML to `stdout`.
+### Linking the two modules together
 
 With the two modules now built, it is time to link them together so that they can be run directly with [Wasmtime](https://github.com/bytecodealliance/wasmtime):
 
 ```text
 $ cargo run --release -- -i markdown=demo/markdown/target/wasm32-wasi/debug/markdown.wasm -p wasmtime -o linked.wasm demo/renderer/target/wasm32-wasi/debug/renderer.wasm
 ```
 
-This command produces a linked module `linked.wasm` that we can now run directly with Wasmtime:
+This command produces a linked module named `linked.wasm` in the current directory.
+
+### Running the linked module
+
+As the linked module uses features from both the [module linking](https://github.com/WebAssembly/module-linking) and [multi-memory](https://github.com/WebAssembly/multi-memory) WebAssembly proposals, support has to be explicitly enabled in Wasmtime to enable the module to run.
+
+To run the linked module:
 
 ```text
 $ echo '# Hello\nworld' | wasmtime --enable-module-linking --enable-multi-memory linked.wasm
 ```
 
-As the linked module uses features from both the [module linking](https://github.com/WebAssembly/module-linking) and [multi-memory](https://github.com/WebAssembly/multi-memory) WebAssembly proposals, support has to be explicitly enabled in Wasmtime to enable the module to run.
-
-If everything worked correctly, this should render the Markdown:
+If everything worked correctly, this should render the Markdown echoed on the command line:
 
 ```markdown
 # Hello

crates/test-modules/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "test-modules"
+version = "0.1.0"
+authors = ["Peter Huene <peter@huene.dev>"]
+edition = "2018"
+
+[dependencies]
+anyhow = "1.0.40"
+wasmlink = { path = "../wasmlink" }
+
+[dev-dependencies]
+wasmtime = "0.27.0"
+wasmtime-wasi = "0.27.0"

crates/test-modules/build.rs

@@ -0,0 +1,38 @@
+use std::{
+    io,
+    process::{Command, Stdio},
+};
+
+fn main() {
+    println!("cargo:rerun-if-changed=modules/crates");
+    println!("cargo:rerun-if-changed=modules/Cargo.toml");
+    println!("cargo:rerun-if-changed=modules/Cargo.lock");
+
+    build_modules().unwrap();
+}
+
+fn build_modules() -> io::Result<()> {
+    let mut cmd = Command::new("cargo");
+
+    cmd.args(&["build", "--target=wasm32-wasi"]);
+
+    if !cfg!(debug_assertions) {
+        cmd.arg("--release");
+    }
+
+    cmd.stdout(Stdio::inherit())
+        .stderr(Stdio::inherit())
+        .current_dir("modules");
+
+    let output = cmd.output()?;
+
+    let status = output.status;
+    if !status.success() {
+        panic!(
+            "Building tests failed: exit code: {}",
+            status.code().unwrap()
+        );
+    }
+
+    Ok(())
+}

crates/test-modules/modules/Cargo.toml

@@ -0,0 +1,5 @@
+[workspace]
+members = [
+    "crates/types",
+    "crates/types-main"
+]

crates/test-modules/modules/crates/types-main/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "types-main"
+version = "0.1.0"
+authors = ["Peter Huene <peter@huene.dev>"]
+edition = "2018"
+
+[dependencies]
+witx-bindgen-rust = { git = "https://github.com/bytecodealliance/witx-bindgen", branch = "main" }

crates/test-modules/modules/crates/types-main/src/main.rs

@@ -0,0 +1,12 @@
+witx_bindgen_rust::import!("crates/types/types.witx");
+
+fn main() {
+    types::a();
+    assert_eq!(types::b(1, 2, 3, 4, 5, 6, 7, 8), (1, 2, 3, 4, 5, 6, 7, 8));
+    assert_eq!(types::c(1.7, 2.6), (1.7, 2.6));
+    assert_eq!(types::d("this is a string"), "this is a string");
+    assert_eq!(types::e(), "hello world!");
+
+    let (a, b, c) = types::f();
+    assert_eq!((a, b.as_str(), c), (13, "hi", 37));
+}

crates/test-modules/modules/crates/types/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "types"
+version = "0.1.0"
+authors = ["Peter Huene <peter@huene.dev>"]
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+witx-bindgen-rust = { git = "https://github.com/bytecodealliance/witx-bindgen", branch = "main" }