From 2f10831a80be2f137baf9a255496316e9563d600 Mon Sep 17 00:00:00 2001
From: Eric Huss <eric@huss.org>
Date: Tue, 22 Apr 2025 08:52:34 -0700
Subject: [PATCH] Migrate relative_command_path to BookTest

---
 tests/alternative_backends.rs | 57 -----------------------------------
 tests/testsuite/renderer.rs   | 54 +++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 57 deletions(-)
 delete mode 100644 tests/alternative_backends.rs

diff --git a/tests/alternative_backends.rs b/tests/alternative_backends.rs
deleted file mode 100644
index 057453b1..00000000
--- a/tests/alternative_backends.rs
+++ /dev/null
@@ -1,57 +0,0 @@
-//! Integration tests to make sure alternative backends work.
-
-use mdbook::config::Config;
-use mdbook::MDBook;
-use std::fs;
-use std::path::Path;
-use tempfile::Builder as TempFileBuilder;
-
-#[test]
-fn relative_command_path() {
-    // Checks behavior of relative paths for the `command` setting.
-    let temp = TempFileBuilder::new().prefix("mdbook").tempdir().unwrap();
-    let renderers = temp.path().join("renderers");
-    fs::create_dir(&renderers).unwrap();
-    rust_exe(
-        &renderers,
-        "myrenderer",
-        r#"fn main() {
-            std::fs::write("output", "test").unwrap();
-        }"#,
-    );
-    let do_test = |cmd_path| {
-        let mut config = Config::default();
-        config
-            .set("output.html", toml::value::Table::new())
-            .unwrap();
-        config.set("output.myrenderer.command", cmd_path).unwrap();
-        let md = MDBook::init(temp.path())
-            .with_config(config)
-            .build()
-            .unwrap();
-        let output = temp.path().join("book/myrenderer/output");
-        assert!(!output.exists());
-        md.build().unwrap();
-        assert!(output.exists());
-        fs::remove_file(output).unwrap();
-    };
-    // Legacy paths work, relative to the output directory.
-    if cfg!(windows) {
-        do_test("../../renderers/myrenderer.exe");
-    } else {
-        do_test("../../renderers/myrenderer");
-    }
-    // Modern path, relative to the book directory.
-    do_test("renderers/myrenderer");
-}
-
-fn rust_exe(temp: &Path, name: &str, src: &str) {
-    let rs = temp.join(name).with_extension("rs");
-    fs::write(&rs, src).unwrap();
-    let status = std::process::Command::new("rustc")
-        .arg(rs)
-        .current_dir(temp)
-        .status()
-        .expect("rustc should run");
-    assert!(status.success());
-}
diff --git a/tests/testsuite/renderer.rs b/tests/testsuite/renderer.rs
index 45f06319..1e162447 100644
--- a/tests/testsuite/renderer.rs
+++ b/tests/testsuite/renderer.rs
@@ -208,3 +208,57 @@ fn backends_receive_render_context_via_stdin() {
     let f = File::open(test.dir.join("book/out.txt")).unwrap();
     RenderContext::from_json(f).unwrap();
 }
+
+// Legacy relative renderer paths.
+//
+// https://github.com/rust-lang/mdBook/pull/1418
+#[test]
+fn legacy_relative_command_path() {
+    let mut test = BookTest::init(|_| {});
+    test.rust_program(
+        "renderers/myrenderer",
+        r#"
+        fn main() {
+            use std::io::Read;
+            let mut s = String::new();
+            std::io::stdin().read_to_string(&mut s).unwrap();
+            std::fs::write("output", "test").unwrap();
+        }
+        "#,
+    )
+    // Test with a modern path, relative to the book directory.
+    .change_file(
+        "book.toml",
+        "[output.myrenderer]\n\
+         command = 'renderers/myrenderer'\n",
+    )
+    .run("build", |cmd| {
+        cmd.expect_stdout(str![[""]]).expect_stderr(str![[r#"
+[TIMESTAMP] [INFO] (mdbook::book): Book building has started
+[TIMESTAMP] [INFO] (mdbook::book): Running the myrenderer backend
+[TIMESTAMP] [INFO] (mdbook::renderer): Invoking the "myrenderer" renderer
+
+"#]]);
+    })
+    .check_file("book/output", "test");
+    std::fs::remove_file(test.dir.join("book/output")).unwrap();
+    // Test with legacy path, relative to the output directory.
+    test.change_file(
+        "book.toml",
+        &format!(
+            "[output.myrenderer]\n\
+             command = '../renderers/myrenderer{exe}'\n",
+            exe = std::env::consts::EXE_SUFFIX
+        ),
+    )
+    .run("build", |cmd| {
+        cmd.expect_stdout(str![[""]]).expect_stderr(str![[r#"
+[TIMESTAMP] [INFO] (mdbook::book): Book building has started
+[TIMESTAMP] [INFO] (mdbook::book): Running the myrenderer backend
+[TIMESTAMP] [INFO] (mdbook::renderer): Invoking the "myrenderer" renderer
+[TIMESTAMP] [WARN] (mdbook::renderer): Renderer command `../renderers/myrenderer[EXE]` uses a path relative to the renderer output directory `[ROOT]/book`. This was previously accepted, but has been deprecated. Relative executable paths should be relative to the book root.
+
+"#]]);
+    })
+    .check_file("book/output", "test");
+}