Test wasmtime-c-api crate (#904)

* Test c-api

.github/workflows/main.yml

@@ -179,7 +179,7 @@ jobs:
       if: matrix.rust == 'nightly'
 
     # Build and test all features except for lightbeam
-    - run: cargo test --features test_programs --all --exclude lightbeam -- --nocapture
+    - run: cargo test --features test_programs --all --exclude lightbeam --exclude wasmtime-c-api -- --nocapture
       env:
         RUST_BACKTRACE: 1
         RUSTFLAGS: "-D warnings"
@@ -194,6 +194,16 @@ jobs:
       env:
         RUST_BACKTRACE: 1
 
+    # Build and test c-api examples. Skipping testing on Windows due to
+    # GNU make dependency when executing the wasm-c-api examples.
+    - run: cargo build --package wasmtime-c-api
+      if: matrix.os == 'ubuntu-latest' || matrix.os == 'macos-latest'
+    - run: cargo test --package wasmtime-c-api -- --nocapture --test-threads 1
+      if: matrix.os == 'ubuntu-latest' || matrix.os == 'macos-latest'
+      continue-on-error: true
+      env:
+        RUST_BACKTRACE: 1
+
   # Builds a Python wheel (package) for Windows/Mac/Linux. Note that we're
   # careful to create binary-compatible releases here to old releases of
   # Windows/Mac/Linux. This will also build wheels for Python 3.6, 3.7 and 3.8.
@@ -317,7 +327,7 @@ jobs:
     - run: $CENTOS cargo build --release --manifest-path crates/c-api/Cargo.toml
       shell: bash
     # Test what we just built
-    - run: $CENTOS cargo test --features test_programs --release --all --exclude lightbeam --exclude wasmtime --exclude wasmtime-fuzzing
+    - run: $CENTOS cargo test --features test_programs --release --all --exclude lightbeam --exclude wasmtime --exclude wasmtime-c-api --exclude wasmtime-fuzzing
       shell: bash
       env:
         RUST_BACKTRACE: 1

crates/c-api/tests/wasm-c-examples.rs

@@ -0,0 +1,198 @@
+use std::env;
+use std::path::PathBuf;
+use std::process::Command;
+
+fn run_c_example(name: &'static str, expected_out: &[u8]) {
+    let cargo = env::var("MAKE").unwrap_or("make".to_string());
+    let pkg_dir = env!("CARGO_MANIFEST_DIR");
+    let examples_dir = PathBuf::from(pkg_dir).join("examples");
+    let make_arg = format!("run-{}-c", name);
+    let output = Command::new(cargo)
+        .current_dir(examples_dir)
+        .args(&["-s", &make_arg])
+        .output()
+        .expect("success");
+    assert!(
+        output.status.success(),
+        "failed to execute the C example '{}': {}",
+        name,
+        String::from_utf8_lossy(&output.stderr),
+    );
+    assert_eq!(
+        output.stdout.as_slice(),
+        expected_out,
+        "unexpected stdout from example: {}",
+        String::from_utf8_lossy(&output.stdout),
+    );
+}
+
+#[test]
+fn test_run_hello_example() {
+    run_c_example(
+        "hello",
+        br#"==== C hello ====
+Initializing...
+Loading binary...
+Compiling module...
+Creating callback...
+Instantiating module...
+Extracting export...
+Calling export...
+Calling back...
+> Hello World!
+Shutting down...
+Done.
+==== Done ====
+"#,
+    );
+}
+
+#[test]
+fn test_run_memory_example() {
+    run_c_example(
+        "memory",
+        br#"==== C memory ====
+Initializing...
+Loading binary...
+Compiling module...
+Instantiating module...
+Extracting exports...
+Checking memory...
+Mutating memory...
+Growing memory...
+Creating stand-alone memory...
+Shutting down...
+Done.
+==== Done ====
+"#,
+    );
+}
+
+#[test]
+fn test_run_global_example() {
+    run_c_example(
+        "global",
+        br#"==== C global ====
+Initializing...
+Loading binary...
+Compiling module...
+Creating globals...
+Instantiating module...
+Extracting exports...
+Accessing globals...
+Shutting down...
+Done.
+==== Done ====
+"#,
+    );
+}
+
+#[test]
+fn test_run_callback_example() {
+    run_c_example(
+        "callback",
+        br#"==== C callback ====
+Initializing...
+Loading binary...
+Compiling module...
+Creating callback...
+Instantiating module...
+Extracting export...
+Calling export...
+Calling back...
+> 7
+Calling back closure...
+> 42
+Printing result...
+> 49
+Shutting down...
+Done.
+==== Done ====
+"#,
+    );
+}
+
+#[test]
+fn test_run_reflect_example() {
+    run_c_example(
+        "reflect",
+        br#"==== C reflect ====
+Initializing...
+Loading binary...
+Compiling module...
+Instantiating module...
+Extracting export...
+> export 0 "func"
+>> initial: func i32 f64 f32 -> i32
+>> current: func i32 f64 f32 -> i32
+>> in-arity: 3, out-arity: 1
+> export 1 "global"
+>> initial: global const f64
+>> current: global const f64
+> export 2 "table"
+>> initial: table 0d 50d funcref
+>> current: table 0d 50d funcref
+> export 3 "memory"
+>> initial: memory 1d
+>> current: memory 1d
+Shutting down...
+Done.
+==== Done ====
+"#,
+    );
+}
+
+#[test]
+fn test_run_start_example() {
+    run_c_example(
+        "start",
+        br#"==== C start ====
+Initializing...
+Loading binary...
+Compiling module...
+Instantiating module...
+Printing message...
+> wasm trap: unreachable, source location: @002e
+Printing origin...
+> Empty origin.
+Printing trace...
+> Empty trace.
+Shutting down...
+Done.
+==== Done ====
+"#,
+    );
+}
+
+#[test]
+fn test_run_trap_example() {
+    run_c_example(
+        "trap",
+        br#"==== C trap ====
+Initializing...
+Loading binary...
+Compiling module...
+Creating callback...
+Instantiating module...
+Extracting exports...
+Calling export 0...
+Calling back...
+Printing message...
+> callback abort
+Printing origin...
+> Empty origin.
+Printing trace...
+> Empty trace.
+Calling export 1...
+Printing message...
+> wasm trap: unreachable, source location: @0065
+Printing origin...
+> Empty origin.
+Printing trace...
+> Empty trace.
+Shutting down...
+Done.
+==== Done ====
+"#,
+    );
+}