Add tests for gen

gen/cmd/Cargo.toml

@@ -32,3 +32,8 @@ miette = { version="4.3", features=["fancy"]}
 [dev-dependencies]
 assert_cmd = "1.0.3"
 tempdir = "0.3.7"
+autocxx-integration-tests = { path = "../../integration-tests", version="0.1" }
+# This is necessary for building the projects created
+# by the trybuild test system...
+autocxx = { path="../.." }
+cxx = "1.0.54"

gen/cmd/tests/cmd_test.rs

@@ -9,12 +9,18 @@
 use std::{convert::TryInto, fs::File, io::Write, path::Path};
 
 use assert_cmd::Command;
+use autocxx_integration_tests::build_from_folder;
 use tempdir::TempDir;
 
-static MAIN_RS: &str = include_str!("../../../demo/src/main.rs");
+static MAIN_RS: &str = concat!(
+    include_str!("../../../demo/src/main.rs"),
+    "#[link(name = \"autocxx-demo\")]\nextern \"C\" {}"
+);
 static INPUT_H: &str = include_str!("../../../demo/src/input.h");
 static BLANK: &str = "// Blank autocxx placeholder";
 
+const KEEP_TEMPDIRS: bool = false;
+
 #[test]
 fn test_help() -> Result<(), Box<dyn std::error::Error>> {
     let mut cmd = Command::cargo_bin("autocxx-gen")?;
@@ -64,7 +70,21 @@ where
 #[test]
 fn test_gen() -> Result<(), Box<dyn std::error::Error>> {
     let tmp_dir = TempDir::new("example")?;
-    base_test(&tmp_dir, |_| {})
+    base_test(&tmp_dir, |_| {})?;
+    File::create(tmp_dir.path().join("cxx.h"))
+        .and_then(|mut cxx_h| cxx_h.write_all(autocxx_engine::HEADER.as_bytes()))?;
+    std::env::set_var("OUT_DIR", tmp_dir.path().to_str().unwrap());
+    let r = build_from_folder(
+        tmp_dir.path(),
+        &tmp_dir.path().join("demo/main.rs"),
+        vec![tmp_dir.path().join("autocxx-ffi-default-gen.rs")],
+        &["gen0.cc"],
+    );
+    if KEEP_TEMPDIRS {
+        println!("Tempdir: {:?}", tmp_dir.into_path().to_str());
+    }
+    r.unwrap();
+    Ok(())
 }
 
 #[test]
@@ -104,6 +124,18 @@ fn test_gen_fixed_num() -> Result<(), Box<dyn std::error::Error>> {
     assert_not_contentful(&tmp_dir, "gen2.h");
     assert_contentful(&tmp_dir, "cxxgen.h");
     assert_contentful(&tmp_dir, "gen.complete.rs");
+    File::create(tmp_dir.path().join("cxx.h"))
+        .and_then(|mut cxx_h| cxx_h.write_all(autocxx_engine::HEADER.as_bytes()))?;
+    let r = build_from_folder(
+        tmp_dir.path(),
+        &tmp_dir.path().join("gen.complete.rs"),
+        vec![],
+        &["gen0.cc"],
+    );
+    if KEEP_TEMPDIRS {
+        println!("Tempdir: {:?}", tmp_dir.into_path().to_str());
+    }
+    r.unwrap();
     Ok(())
 }
 

integration-tests/src/lib.rs

@@ -15,7 +15,9 @@ use std::{
     sync::Mutex,
 };
 
-use autocxx_engine::{Builder, BuilderContext, BuilderError, RebuildDependencyRecorder, HEADER};
+use autocxx_engine::{
+    Builder, BuilderBuild, BuilderContext, BuilderError, RebuildDependencyRecorder, HEADER,
+};
 use log::info;
 use once_cell::sync::OnceCell;
 use proc_macro2::{Span, TokenStream};
@@ -38,6 +40,50 @@ pub fn doctest(
     do_run_test_manual(cxx_code, header_code, rust_code, None, None)
 }
 
+fn configure_builder(b: &mut BuilderBuild) -> &mut BuilderBuild {
+    let target = rust_info::get().target_triple.unwrap();
+    b.host(&target)
+        .target(&target)
+        .opt_level(1)
+        .flag("-std=c++14") // For clang
+        .flag_if_supported("/GX") // Enable C++ exceptions for msvc
+}
+
+/// API to test building pre-generated files.
+pub fn build_from_folder(
+    folder: &Path,
+    main_rs_file: &Path,
+    generated_rs_files: Vec<PathBuf>,
+    cpp_files: &[&str],
+) -> Result<(), TestError> {
+    let target_dir = folder.join("target");
+    std::fs::create_dir(&target_dir).unwrap();
+    let mut b = BuilderBuild::new();
+    for cpp_file in cpp_files.iter() {
+        b.file(folder.join(cpp_file));
+    }
+    configure_builder(&mut b)
+        .out_dir(&target_dir)
+        .include(folder)
+        .include(folder.join("demo"))
+        .try_compile("autocxx-demo")
+        .map_err(TestError::CppBuild)?;
+    // use the trybuild crate to build the Rust file.
+    let r = get_builder().lock().unwrap().build(
+        &target_dir,
+        "autocxx-demo",
+        &folder,
+        &["input.h", "cxx.h"],
+        &main_rs_file,
+        generated_rs_files,
+    );
+    if r.is_err() {
+        return Err(TestError::RsBuild); // details of Rust panic are a bit messy to include, and
+                                        // not important at the moment.
+    }
+    Ok(())
+}
+
 fn get_builder() -> &'static Mutex<LinkableTryBuilder> {
     static INSTANCE: OnceCell<Mutex<LinkableTryBuilder>> = OnceCell::new();
     INSTANCE.get_or_init(|| Mutex::new(LinkableTryBuilder::new()))
@@ -375,8 +421,6 @@ pub fn do_run_test_manual(
         }
     }
 
-    let target = rust_info::get().target_triple.unwrap();
-
     if !cxx_code.is_empty() {
         // Step 4: Write the C++ code snippet to a .cc file, along with a #include
         //         of the header emitted in step 5.
@@ -385,13 +429,7 @@ pub fn do_run_test_manual(
         b.file(cxx_path);
     }
 
-    let b = b
-        .out_dir(&target_dir)
-        .host(&target)
-        .target(&target)
-        .opt_level(1)
-        .flag("-std=c++14") // For clang
-        .flag_if_supported("/GX"); // Enable C++ exceptions for msvc
+    let b = configure_builder(&mut b).out_dir(&target_dir);
     let b = if let Some(builder_modifier) = builder_modifier {
         builder_modifier.modify_cc_builder(b)
     } else {