Add print snapshot tests

firmware/qemu/write_output.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+bins=("assert" "assert-eq" "assert-ne" "bitflags" "dbg" "hints" "hints_inner" "log" "panic" "panic_info" "timestamp" "unwrap")
+
+echo "Generating output ..."
+
+for value in "${bins[@]}"; do
+	command="DEFMT_LOG=trace cargo -q run --features no-decode --manifest-path ../../qemu-run/Cargo.toml ../target/thumbv7m-none-eabi/debug/$value > ~/defmt/xtask/output_files/$value.out"
+	echo "$command"
+	eval "$command"
+done

qemu-run/Cargo.toml

@@ -9,3 +9,6 @@ version = "0.0.0"
 [dependencies]
 anyhow = "1"
 defmt-decoder = { version = "=0.4.0", path = "../decoder" }
+
+[features]
+no-decode = []

qemu-run/src/main.rs

@@ -5,7 +5,7 @@
 
 use std::{
     env, fs,
-    io::Read as _,
+    io::{self, Read as _, Write},
     process::{self, Command, Stdio},
 };
 
@@ -70,8 +70,12 @@ fn notmain() -> Result<Option<i32>, anyhow::Error> {
     let exit_code;
     loop {
         let n = stdout.read(&mut readbuf)?;
-        decoder.received(&readbuf[..n]);
-        decode(&mut *decoder)?;
+        if cfg!(feature = "no-decode") {
+            io::stdout().write_all(&readbuf[..n])?;
+        } else {
+            decoder.received(&readbuf[..n]);
+            decode(&mut *decoder)?;
+        }
 
         if let Some(status) = child.0.try_wait()? {
             exit_code = status.code();

xtask/src/main.rs

@@ -1,4 +1,5 @@
 mod backcompat;
+mod print_snapshot;
 mod snapshot;
 mod targets;
 mod utils;
@@ -9,6 +10,7 @@ use anyhow::anyhow;
 use clap::{Parser, Subcommand};
 use utils::rustc_is_msrv;
 
+use crate::print_snapshot::test_print_snapshot;
 use crate::{
     snapshot::{test_snapshot, Snapshot},
     utils::{run_capturing_stdout, run_command},
@@ -48,6 +50,10 @@ enum TestCommand {
         /// Runs a single snapshot test in Debug mode
         single: Option<Snapshot>,
     },
+    TestPrintSnapshot {
+        /// Runs a single snapshot test in Debug mode
+        single: Option<Snapshot>,
+    },
 }
 
 fn main() -> anyhow::Result<()> {
@@ -77,6 +83,7 @@ fn main() -> anyhow::Result<()> {
                     test_book();
                     test_lint();
                 }
+                TestCommand::TestPrintSnapshot { single } => test_print_snapshot(single),
                 _ => unreachable!("get handled in outer `match`"),
             }
         }

xtask/src/print_snapshot.rs

@@ -0,0 +1,69 @@
+use crate::do_test;
+use crate::snapshot::{all_snapshot_tests, Snapshot};
+use crate::utils::{load_expected_output, run_capturing_stdout};
+use anyhow::{anyhow, Context};
+use colored::Colorize;
+use similar::{ChangeTag, TextDiff};
+use std::process::{Command, Stdio};
+
+pub fn test_print_snapshot(snapshot: Option<Snapshot>) {
+    match snapshot {
+        None => test_all_print_snapshots(),
+        Some(snapshot) => {
+            do_test(
+                || test_single_print_snapshot(snapshot.name()),
+                "qemu/snapshot_print",
+            );
+        }
+    }
+}
+
+pub fn test_all_print_snapshots() {
+    for test in all_snapshot_tests() {
+        do_test(|| test_single_print_snapshot(test), "qemu/snapshot_print");
+    }
+}
+
+pub fn test_single_print_snapshot(name: &str) -> anyhow::Result<()> {
+    println!("{}", name.bold());
+
+    let frame_path = format!("xtask/output_files/{}.out", name);
+    let elf_path = format!("xtask/snapshot_elfs/{}", name);
+
+    let frames = std::fs::File::open(frame_path)?;
+
+    let actual = run_capturing_stdout(
+        Command::new("defmt-print")
+            .arg("-e")
+            .arg(elf_path)
+            .arg("--log-format")
+            .arg("{L:4} {s}")
+            .stdin(Stdio::from(frames)),
+    )
+    .with_context(|| name.to_string())?;
+
+    let expected = load_expected_output(name, false)?;
+    let diff = TextDiff::from_lines(&expected, &actual);
+
+    // if anything isn't ChangeTag::Equal, print it and turn on error flag
+    let mut actual_matches_expected = true;
+    for op in diff.ops() {
+        for change in diff.iter_changes(op) {
+            let styled_change = match change.tag() {
+                ChangeTag::Delete => Some(("-".bold().red(), change.to_string().red())),
+                ChangeTag::Insert => Some(("+".bold().green(), change.to_string().green())),
+                ChangeTag::Equal => None,
+            };
+            if let Some((sign, change)) = styled_change {
+                actual_matches_expected = false;
+                eprint!("{sign}{change}");
+            }
+        }
+    }
+
+    if actual_matches_expected {
+        Ok(())
+    } else {
+        Err(anyhow!("{}", name))
+    }
+}