Merge #604

604: defmt-test: `#[cfg(test)]` the `#[defmt_test::tests]` module r=Urhengulas a=japaric

[it recently came to my attention](knurling-rs/app-template@1ebc0ac) that one can use `defmt-test` for "unit testing" by using it in `src/lib.rs` (although this is pretty limited at the moment because one can only use the `defmt_test::tests` *once* in a library crate)

if one does use `defmt_test` like that then they may run into the issue that running the test files in `tests` fails with this cryptic linker message: 

``` console
  = note: rust-lld: error: duplicate symbol: main
```

the issue is that the code generated by `defmt_test::tests` (which includes a function with unmangled name `main`) is not conditionally compiled but we do want that to be `#[cfg(test)]`-ed because it contains test code.

r? `@jonas-schievink` 

Co-authored-by: Jorge Aparicio <jorge.aparicio@ferrous-systems.com>

Author: bors[bot]

firmware/defmt-test/macros/src/lib.rs

@@ -214,7 +214,9 @@ fn tests_impl(args: TokenStream, input: TokenStream) -> parse::Result<TokenStrea
             }
         })
         .collect::<Vec<_>>();
-    Ok(quote!(mod #ident {
+    Ok(quote!(
+    #[cfg(test)]
+    mod #ident {
         #(#untouched_tokens)*
         // TODO use `cortex-m-rt::entry` here to get the `static mut` transform
         #[export_name = "main"]

firmware/qemu/.cargo/config.toml

@@ -1,4 +1,5 @@
 [alias]
+tt = "-q test --target thumbv7m-none-eabi --test"
 rb = "-q run --target thumbv7m-none-eabi --bin"
 rrb = "-q run --target thumbv7m-none-eabi --release --bin"
 

firmware/qemu/Cargo.toml

@@ -6,6 +6,10 @@ name = "firmware"
 publish = false
 version = "0.1.0"
 
+[[test]]
+name = "defmt-test"
+harness = false
+
 [dependencies]
 defmt = { path = "../../defmt" }
 defmt-semihosting = { path = "../defmt-semihosting" }

firmware/qemu/tests/.gitignore

@@ -0,0 +1 @@
+*.new

firmware/qemu/src/bin/defmt-test.out firmware/qemu/tests/defmt-test.outfirmware/qemu/src/bin/defmt-test.out renamed to firmware/qemu/tests/defmt-test.out

@@ -98,9 +98,12 @@ impl QemuRun {
     fn run_snapshot(&self, name: &str) -> anyhow::Result<()> {
         println!("{}", name.bold());
 
+        let is_test = name.contains("test");
+        let command = if is_test { "tt" } else { "rb" };
+
         run_silently(
             Command::new("cargo")
-                .args(["-q", "rb", name])
+                .args(["-q", command, name])
                 .current_dir(SNAPSHOT_TESTS_DIRECTORY)
                 .env(RUNNER_ENV_VAR, self.path()),
             || anyhow!("{}", name.to_string()),

firmware/qemu/src/bin/defmt-test.rs firmware/qemu/tests/defmt-test.rsfirmware/qemu/src/bin/defmt-test.rs renamed to firmware/qemu/tests/defmt-test.rs

@@ -331,7 +331,13 @@ fn test_all_snapshots(overwrite: bool) {
 fn test_single_snapshot(name: &str, features: &str, overwrite: bool) -> anyhow::Result<()> {
     println!("{}", name.bold());
 
-    let mut args = vec!["-q", "rb", name];
+    let is_test = name.contains("test");
+
+    let mut args = if is_test {
+        vec!["-q", "tt", name]
+    } else {
+        vec!["-q", "rb", name]
+    };
 
     if !features.is_empty() {
         args.extend_from_slice(&["--features", features]);
@@ -346,11 +352,11 @@ fn test_single_snapshot(name: &str, features: &str, overwrite: bool) -> anyhow::
     .with_context(|| name.to_string())?;
 
     if overwrite {
-        overwrite_expected_output(name, actual.as_bytes())?;
+        overwrite_expected_output(name, actual.as_bytes(), is_test)?;
         return Ok(());
     }
 
-    let expected = load_expected_output(name)?;
+    let expected = load_expected_output(name, is_test)?;
     let diff = TextDiff::from_lines(&expected, &actual);
 
     // if anything isn't ChangeTag::Equal, print it and turn on error flag

xtask/src/backcompat.rs

@@ -1,22 +1,26 @@
-use std::{fs, path::Path, process::Command, str};
+use std::{
+    fs,
+    path::{Path, PathBuf},
+    process::Command,
+    str,
+};
 
 use anyhow::{anyhow, Context};
 use colored::Colorize;
 
-pub fn load_expected_output(name: &str) -> anyhow::Result<String> {
-    let file = expected_output_path(name);
-    let path = Path::new(&file);
+pub fn load_expected_output(name: &str, is_test: bool) -> anyhow::Result<String> {
+    let path = expected_output_path(name, is_test);
 
-    fs::read_to_string(path).with_context(|| {
+    fs::read_to_string(&path).with_context(|| {
         format!(
             "Failed to load expected output data from {}",
             path.to_str().unwrap_or("(non-Unicode path)")
         )
     })
 }
 
-pub fn overwrite_expected_output(name: &str, contents: &[u8]) -> anyhow::Result<()> {
-    let file = expected_output_path(name);
+pub fn overwrite_expected_output(name: &str, contents: &[u8], is_test: bool) -> anyhow::Result<()> {
+    let file = expected_output_path(name, is_test);
     let path = Path::new(&file);
 
     fs::write(path, contents).with_context(|| {
@@ -27,9 +31,19 @@ pub fn overwrite_expected_output(name: &str, contents: &[u8]) -> anyhow::Result<
     })
 }
 
-fn expected_output_path(name: &str) -> String {
-    const BASE: &str = "firmware/qemu/src/bin";
-    format!("{}/{}.out", BASE, name)
+fn expected_output_path(name: &str, is_test: bool) -> PathBuf {
+    const PROJECT_DIR: &str = "firmware/qemu";
+
+    let mut path = PathBuf::from(PROJECT_DIR);
+    if is_test {
+        path.push("tests")
+    } else {
+        path.push("src");
+        path.push("bin");
+    };
+    path.push(name);
+    path.set_extension("out");
+    path
 }
 
 /// Execute the [`Command`]. If success return `stdout`, if failure print to `stderr`