Break up uv-build/src/lib.rs (#7238)

crates/uv-build/src/error.rs

@@ -0,0 +1,369 @@
+use itertools::Itertools;
+use regex::Regex;
+use std::env;
+use std::fmt::{Display, Formatter};
+use std::io;
+use std::path::PathBuf;
+use std::process::ExitStatus;
+use std::sync::LazyLock;
+use thiserror::Error;
+use tracing::error;
+
+use crate::PythonRunnerOutput;
+use uv_configuration::BuildOutput;
+use uv_fs::Simplified;
+
+/// e.g. `pygraphviz/graphviz_wrap.c:3020:10: fatal error: graphviz/cgraph.h: No such file or directory`
+static MISSING_HEADER_RE_GCC: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(
+        r".*\.(?:c|c..|h|h..):\d+:\d+: fatal error: (.*\.(?:h|h..)): No such file or directory",
+    )
+    .unwrap()
+});
+
+/// e.g. `pygraphviz/graphviz_wrap.c:3023:10: fatal error: 'graphviz/cgraph.h' file not found`
+static MISSING_HEADER_RE_CLANG: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(r".*\.(?:c|c..|h|h..):\d+:\d+: fatal error: '(.*\.(?:h|h..))' file not found")
+        .unwrap()
+});
+
+/// e.g. `pygraphviz/graphviz_wrap.c(3023): fatal error C1083: Cannot open include file: 'graphviz/cgraph.h': No such file or directory`
+static MISSING_HEADER_RE_MSVC: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(r".*\.(?:c|c..|h|h..)\(\d+\): fatal error C1083: Cannot open include file: '(.*\.(?:h|h..))': No such file or directory")
+        .unwrap()
+});
+
+/// e.g. `/usr/bin/ld: cannot find -lncurses: No such file or directory`
+static LD_NOT_FOUND_RE: LazyLock<Regex> = LazyLock::new(|| {
+    Regex::new(r"/usr/bin/ld: cannot find -l([a-zA-Z10-9]+): No such file or directory").unwrap()
+});
+
+/// e.g. `error: invalid command 'bdist_wheel'`
+static WHEEL_NOT_FOUND_RE: LazyLock<Regex> =
+    LazyLock::new(|| Regex::new(r"error: invalid command 'bdist_wheel'").unwrap());
+
+/// e.g. `ModuleNotFoundError: No module named 'torch'`
+static TORCH_NOT_FOUND_RE: LazyLock<Regex> =
+    LazyLock::new(|| Regex::new(r"ModuleNotFoundError: No module named 'torch'").unwrap());
+
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error(transparent)]
+    Io(#[from] io::Error),
+    #[error("{} does not appear to be a Python project, as neither `pyproject.toml` nor `setup.py` are present in the directory", _0.simplified_display())]
+    InvalidSourceDist(PathBuf),
+    #[error("Invalid `pyproject.toml`")]
+    InvalidPyprojectToml(#[from] toml::de::Error),
+    #[error("Editable installs with setup.py legacy builds are unsupported, please specify a build backend in pyproject.toml")]
+    EditableSetupPy,
+    #[error("Failed to install requirements from {0}")]
+    RequirementsInstall(&'static str, #[source] anyhow::Error),
+    #[error("Failed to create temporary virtualenv")]
+    Virtualenv(#[from] uv_virtualenv::Error),
+    #[error("Failed to run `{0}`")]
+    CommandFailed(PathBuf, #[source] io::Error),
+    #[error("{message} with {exit_code}\n--- stdout:\n{stdout}\n--- stderr:\n{stderr}\n---")]
+    BuildBackendOutput {
+        message: String,
+        exit_code: ExitStatus,
+        stdout: String,
+        stderr: String,
+    },
+    /// Nudge the user towards installing the missing dev library
+    #[error("{message} with {exit_code}\n--- stdout:\n{stdout}\n--- stderr:\n{stderr}\n---")]
+    MissingHeaderOutput {
+        message: String,
+        exit_code: ExitStatus,
+        stdout: String,
+        stderr: String,
+        #[source]
+        missing_header_cause: MissingHeaderCause,
+    },
+    #[error("{message} with {exit_code}")]
+    BuildBackend {
+        message: String,
+        exit_code: ExitStatus,
+    },
+    #[error("{message} with {exit_code}")]
+    MissingHeader {
+        message: String,
+        exit_code: ExitStatus,
+        #[source]
+        missing_header_cause: MissingHeaderCause,
+    },
+    #[error("Failed to build PATH for build script")]
+    BuildScriptPath(#[source] env::JoinPathsError),
+}
+
+#[derive(Debug)]
+enum MissingLibrary {
+    Header(String),
+    Linker(String),
+    PythonPackage(String),
+}
+
+#[derive(Debug, Error)]
+pub struct MissingHeaderCause {
+    missing_library: MissingLibrary,
+    version_id: String,
+}
+
+impl Display for MissingHeaderCause {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match &self.missing_library {
+            MissingLibrary::Header(header) => {
+                write!(
+                    f,
+                    "This error likely indicates that you need to install a library that provides \"{}\" for {}",
+                    header, self.version_id
+                )
+            }
+            MissingLibrary::Linker(library) => {
+                write!(
+                    f,
+                    "This error likely indicates that you need to install the library that provides a shared library \
+                    for {library} for {version_id} (e.g. lib{library}-dev)",
+                    library = library, version_id = self.version_id
+                )
+            }
+            MissingLibrary::PythonPackage(package) => {
+                write!(
+                    f,
+                    "This error likely indicates that {version_id} depends on {package}, but doesn't declare it as a build dependency. \
+                        If {version_id} is a first-party package, consider adding {package} to its `build-system.requires`. \
+                        Otherwise, `uv pip install {package}` into the environment and re-run with `--no-build-isolation`.",
+                    package = package, version_id = self.version_id
+                )
+            }
+        }
+    }
+}
+
+impl Error {
+    pub(crate) fn from_command_output(
+        message: String,
+        output: &PythonRunnerOutput,
+        level: BuildOutput,
+        version_id: impl Into<String>,
+    ) -> Self {
+        // In the cases I've seen it was the 5th and 3rd last line (see test case), 10 seems like a reasonable cutoff.
+        let missing_library = output.stderr.iter().rev().take(10).find_map(|line| {
+            if let Some((_, [header])) = MISSING_HEADER_RE_GCC
+                .captures(line.trim())
+                .or(MISSING_HEADER_RE_CLANG.captures(line.trim()))
+                .or(MISSING_HEADER_RE_MSVC.captures(line.trim()))
+                .map(|c| c.extract())
+            {
+                Some(MissingLibrary::Header(header.to_string()))
+            } else if let Some((_, [library])) =
+                LD_NOT_FOUND_RE.captures(line.trim()).map(|c| c.extract())
+            {
+                Some(MissingLibrary::Linker(library.to_string()))
+            } else if WHEEL_NOT_FOUND_RE.is_match(line.trim()) {
+                Some(MissingLibrary::PythonPackage("wheel".to_string()))
+            } else if TORCH_NOT_FOUND_RE.is_match(line.trim()) {
+                Some(MissingLibrary::PythonPackage("torch".to_string()))
+            } else {
+                None
+            }
+        });
+
+        if let Some(missing_library) = missing_library {
+            return match level {
+                BuildOutput::Stderr => Self::MissingHeader {
+                    message,
+                    exit_code: output.status,
+                    missing_header_cause: MissingHeaderCause {
+                        missing_library,
+                        version_id: version_id.into(),
+                    },
+                },
+                BuildOutput::Debug => Self::MissingHeaderOutput {
+                    message,
+                    exit_code: output.status,
+                    stdout: output.stdout.iter().join("\n"),
+                    stderr: output.stderr.iter().join("\n"),
+                    missing_header_cause: MissingHeaderCause {
+                        missing_library,
+                        version_id: version_id.into(),
+                    },
+                },
+            };
+        }
+
+        match level {
+            BuildOutput::Stderr => Self::BuildBackend {
+                message,
+                exit_code: output.status,
+            },
+            BuildOutput::Debug => Self::BuildBackendOutput {
+                message,
+                exit_code: output.status,
+                stdout: output.stdout.iter().join("\n"),
+                stderr: output.stderr.iter().join("\n"),
+            },
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use std::process::ExitStatus;
+
+    use crate::{Error, PythonRunnerOutput};
+    use indoc::indoc;
+    use uv_configuration::BuildOutput;
+
+    #[test]
+    fn missing_header() {
+        let output = PythonRunnerOutput {
+            status: ExitStatus::default(), // This is wrong but `from_raw` is platform-gated.
+            stdout: indoc!(r"
+                running bdist_wheel
+                running build
+                [...]
+                creating build/temp.linux-x86_64-cpython-39/pygraphviz
+                gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DOPENSSL_NO_SSL3 -fPIC -DSWIG_PYTHON_STRICT_BYTE_CHAR -I/tmp/.tmpy6vVes/.venv/include -I/home/konsti/.pyenv/versions/3.9.18/include/python3.9 -c pygraphviz/graphviz_wrap.c -o build/temp.linux-x86_64-cpython-39/pygraphviz/graphviz_wrap.o
+                "
+            ).lines().map(ToString::to_string).collect(),
+            stderr: indoc!(r#"
+                warning: no files found matching '*.png' under directory 'doc'
+                warning: no files found matching '*.txt' under directory 'doc'
+                [...]
+                no previously-included directories found matching 'doc/build'
+                pygraphviz/graphviz_wrap.c:3020:10: fatal error: graphviz/cgraph.h: No such file or directory
+                 3020 | #include "graphviz/cgraph.h"
+                      |          ^~~~~~~~~~~~~~~~~~~
+                compilation terminated.
+                error: command '/usr/bin/gcc' failed with exit code 1
+                "#
+            ).lines().map(ToString::to_string).collect(),
+        };
+
+        let err = Error::from_command_output(
+            "Failed building wheel through setup.py".to_string(),
+            &output,
+            BuildOutput::Debug,
+            "pygraphviz-1.11",
+        );
+        assert!(matches!(err, Error::MissingHeaderOutput { .. }));
+        // Unix uses exit status, Windows uses exit code.
+        let formatted = err.to_string().replace("exit status: ", "exit code: ");
+        insta::assert_snapshot!(formatted, @r###"
+        Failed building wheel through setup.py with exit code: 0
+        --- stdout:
+        running bdist_wheel
+        running build
+        [...]
+        creating build/temp.linux-x86_64-cpython-39/pygraphviz
+        gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DOPENSSL_NO_SSL3 -fPIC -DSWIG_PYTHON_STRICT_BYTE_CHAR -I/tmp/.tmpy6vVes/.venv/include -I/home/konsti/.pyenv/versions/3.9.18/include/python3.9 -c pygraphviz/graphviz_wrap.c -o build/temp.linux-x86_64-cpython-39/pygraphviz/graphviz_wrap.o
+        --- stderr:
+        warning: no files found matching '*.png' under directory 'doc'
+        warning: no files found matching '*.txt' under directory 'doc'
+        [...]
+        no previously-included directories found matching 'doc/build'
+        pygraphviz/graphviz_wrap.c:3020:10: fatal error: graphviz/cgraph.h: No such file or directory
+         3020 | #include "graphviz/cgraph.h"
+              |          ^~~~~~~~~~~~~~~~~~~
+        compilation terminated.
+        error: command '/usr/bin/gcc' failed with exit code 1
+        ---
+        "###);
+        insta::assert_snapshot!(
+            std::error::Error::source(&err).unwrap(),
+            @r###"This error likely indicates that you need to install a library that provides "graphviz/cgraph.h" for pygraphviz-1.11"###
+        );
+    }
+
+    #[test]
+    fn missing_linker_library() {
+        let output = PythonRunnerOutput {
+            status: ExitStatus::default(), // This is wrong but `from_raw` is platform-gated.
+            stdout: Vec::new(),
+            stderr: indoc!(
+                r"
+               1099 |     n = strlen(p);
+                    |         ^~~~~~~~~
+               /usr/bin/ld: cannot find -lncurses: No such file or directory
+               collect2: error: ld returned 1 exit status
+               error: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1"
+            )
+            .lines()
+            .map(ToString::to_string)
+            .collect(),
+        };
+
+        let err = Error::from_command_output(
+            "Failed building wheel through setup.py".to_string(),
+            &output,
+            BuildOutput::Debug,
+            "pygraphviz-1.11",
+        );
+        assert!(matches!(err, Error::MissingHeaderOutput { .. }));
+        // Unix uses exit status, Windows uses exit code.
+        let formatted = err.to_string().replace("exit status: ", "exit code: ");
+        insta::assert_snapshot!(formatted, @r###"
+        Failed building wheel through setup.py with exit code: 0
+        --- stdout:
+
+        --- stderr:
+        1099 |     n = strlen(p);
+             |         ^~~~~~~~~
+        /usr/bin/ld: cannot find -lncurses: No such file or directory
+        collect2: error: ld returned 1 exit status
+        error: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1
+        ---
+        "###);
+        insta::assert_snapshot!(
+            std::error::Error::source(&err).unwrap(),
+            @"This error likely indicates that you need to install the library that provides a shared library for ncurses for pygraphviz-1.11 (e.g. libncurses-dev)"
+        );
+    }
+
+    #[test]
+    fn missing_wheel_package() {
+        let output = PythonRunnerOutput {
+            status: ExitStatus::default(), // This is wrong but `from_raw` is platform-gated.
+            stdout: Vec::new(),
+            stderr: indoc!(
+                r"
+            usage: setup.py [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
+               or: setup.py --help [cmd1 cmd2 ...]
+               or: setup.py --help-commands
+               or: setup.py cmd --help
+
+            error: invalid command 'bdist_wheel'"
+            )
+            .lines()
+            .map(ToString::to_string)
+            .collect(),
+        };
+
+        let err = Error::from_command_output(
+            "Failed building wheel through setup.py".to_string(),
+            &output,
+            BuildOutput::Debug,
+            "pygraphviz-1.11",
+        );
+        assert!(matches!(err, Error::MissingHeaderOutput { .. }));
+        // Unix uses exit status, Windows uses exit code.
+        let formatted = err.to_string().replace("exit status: ", "exit code: ");
+        insta::assert_snapshot!(formatted, @r###"
+        Failed building wheel through setup.py with exit code: 0
+        --- stdout:
+
+        --- stderr:
+        usage: setup.py [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
+           or: setup.py --help [cmd1 cmd2 ...]
+           or: setup.py --help-commands
+           or: setup.py cmd --help
+
+        error: invalid command 'bdist_wheel'
+        ---
+        "###);
+        insta::assert_snapshot!(
+            std::error::Error::source(&err).unwrap(),
+            @"This error likely indicates that pygraphviz-1.11 depends on wheel, but doesn't declare it as a build dependency. If pygraphviz-1.11 is a first-party package, consider adding wheel to its `build-system.requires`. Otherwise, `uv pip install wheel` into the environment and re-run with `--no-build-isolation`."
+        );
+    }
+}

crates/uv-build/src/lib.rs

@@ -1,17 +1,18 @@
-//! Build wheels from source distributions
+//! Build wheels from source distributions.
 //!
 //! <https://packaging.python.org/en/latest/specifications/source-distribution-format/>
 
+mod error;
+
 use fs_err as fs;
 use indoc::formatdoc;
 use itertools::Itertools;
-use regex::Regex;
 use rustc_hash::FxHashMap;
 use serde::de::{value, SeqAccess, Visitor};
 use serde::{de, Deserialize, Deserializer};
 use std::ffi::OsString;
+use std::fmt::Formatter;
 use std::fmt::Write;
-use std::fmt::{Display, Formatter};
 use std::io;
 use std::path::{Path, PathBuf};
 use std::process::ExitStatus;
@@ -20,12 +21,12 @@ use std::str::FromStr;
 use std::sync::LazyLock;
 use std::{env, iter};
 use tempfile::{tempdir_in, TempDir};
-use thiserror::Error;
 use tokio::io::AsyncBufReadExt;
 use tokio::process::Command;
 use tokio::sync::{Mutex, Semaphore};
-use tracing::{debug, error, info_span, instrument, Instrument};
+use tracing::{debug, info_span, instrument, Instrument};
 
+pub use crate::error::{Error, MissingHeaderCause};
 use distribution_types::Resolution;
 use pep440_rs::Version;
 use pep508_rs::PackageName;
@@ -35,39 +36,6 @@ use uv_fs::{rename_with_retry, PythonExt, Simplified};
 use uv_python::{Interpreter, PythonEnvironment};
 use uv_types::{BuildContext, BuildIsolation, SourceBuildTrait};
 
-/// e.g. `pygraphviz/graphviz_wrap.c:3020:10: fatal error: graphviz/cgraph.h: No such file or directory`
-static MISSING_HEADER_RE_GCC: LazyLock<Regex> = LazyLock::new(|| {
-    Regex::new(
-        r".*\.(?:c|c..|h|h..):\d+:\d+: fatal error: (.*\.(?:h|h..)): No such file or directory",
-    )
-    .unwrap()
-});
-
-/// e.g. `pygraphviz/graphviz_wrap.c:3023:10: fatal error: 'graphviz/cgraph.h' file not found`
-static MISSING_HEADER_RE_CLANG: LazyLock<Regex> = LazyLock::new(|| {
-    Regex::new(r".*\.(?:c|c..|h|h..):\d+:\d+: fatal error: '(.*\.(?:h|h..))' file not found")
-        .unwrap()
-});
-
-/// e.g. `pygraphviz/graphviz_wrap.c(3023): fatal error C1083: Cannot open include file: 'graphviz/cgraph.h': No such file or directory`
-static MISSING_HEADER_RE_MSVC: LazyLock<Regex> = LazyLock::new(|| {
-    Regex::new(r".*\.(?:c|c..|h|h..)\(\d+\): fatal error C1083: Cannot open include file: '(.*\.(?:h|h..))': No such file or directory")
-        .unwrap()
-});
-
-/// e.g. `/usr/bin/ld: cannot find -lncurses: No such file or directory`
-static LD_NOT_FOUND_RE: LazyLock<Regex> = LazyLock::new(|| {
-    Regex::new(r"/usr/bin/ld: cannot find -l([a-zA-Z10-9]+): No such file or directory").unwrap()
-});
-
-/// e.g. `error: invalid command 'bdist_wheel'`
-static WHEEL_NOT_FOUND_RE: LazyLock<Regex> =
-    LazyLock::new(|| Regex::new(r"error: invalid command 'bdist_wheel'").unwrap());
-
-/// e.g. `ModuleNotFoundError: No module named 'torch'`
-static TORCH_NOT_FOUND_RE: LazyLock<Regex> =
-    LazyLock::new(|| Regex::new(r"ModuleNotFoundError: No module named 'torch'").unwrap());
-
 /// The default backend to use when PEP 517 is used without a `build-system` section.
 static DEFAULT_BACKEND: LazyLock<Pep517Backend> = LazyLock::new(|| Pep517Backend {
     backend: "setuptools.build_meta:__legacy__".to_string(),
@@ -77,197 +45,6 @@ static DEFAULT_BACKEND: LazyLock<Pep517Backend> = LazyLock::new(|| Pep517Backend
     )],
 });
 
-#[derive(Error, Debug)]
-pub enum Error {
-    #[error(transparent)]
-    Io(#[from] io::Error),
-    #[error("{} does not appear to be a Python project, as neither `pyproject.toml` nor `setup.py` are present in the directory", _0.simplified_display())]
-    InvalidSourceDist(PathBuf),
-    #[error("Invalid `pyproject.toml`")]
-    InvalidPyprojectToml(#[from] toml::de::Error),
-    #[error("Editable installs with setup.py legacy builds are unsupported, please specify a build backend in pyproject.toml")]
-    EditableSetupPy,
-    #[error("Failed to install requirements from {0}")]
-    RequirementsInstall(&'static str, #[source] anyhow::Error),
-    #[error("Failed to create temporary virtualenv")]
-    Virtualenv(#[from] uv_virtualenv::Error),
-    #[error("Failed to run `{0}`")]
-    CommandFailed(PathBuf, #[source] io::Error),
-    #[error("{message} with {exit_code}\n--- stdout:\n{stdout}\n--- stderr:\n{stderr}\n---")]
-    BuildBackendOutput {
-        message: String,
-        exit_code: ExitStatus,
-        stdout: String,
-        stderr: String,
-    },
-    /// Nudge the user towards installing the missing dev library
-    #[error("{message} with {exit_code}\n--- stdout:\n{stdout}\n--- stderr:\n{stderr}\n---")]
-    MissingHeaderOutput {
-        message: String,
-        exit_code: ExitStatus,
-        stdout: String,
-        stderr: String,
-        #[source]
-        missing_header_cause: MissingHeaderCause,
-    },
-    #[error("{message} with {exit_code}")]
-    BuildBackend {
-        message: String,
-        exit_code: ExitStatus,
-    },
-    #[error("{message} with {exit_code}")]
-    MissingHeader {
-        message: String,
-        exit_code: ExitStatus,
-        #[source]
-        missing_header_cause: MissingHeaderCause,
-    },
-    #[error("Failed to build PATH for build script")]
-    BuildScriptPath(#[source] env::JoinPathsError),
-}
-
-#[derive(Debug)]
-enum MissingLibrary {
-    Header(String),
-    Linker(String),
-    PythonPackage(String),
-}
-
-#[derive(Debug, Error)]
-pub struct MissingHeaderCause {
-    missing_library: MissingLibrary,
-    version_id: String,
-}
-
-impl Display for MissingHeaderCause {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        match &self.missing_library {
-            MissingLibrary::Header(header) => {
-                write!(
-                    f,
-                    "This error likely indicates that you need to install a library that provides \"{}\" for {}",
-                    header, self.version_id
-                )
-            }
-            MissingLibrary::Linker(library) => {
-                write!(
-                    f,
-                    "This error likely indicates that you need to install the library that provides a shared library \
-                    for {library} for {version_id} (e.g. lib{library}-dev)",
-                    library = library, version_id = self.version_id
-                )
-            }
-            MissingLibrary::PythonPackage(package) => {
-                write!(
-                    f,
-                    "This error likely indicates that {version_id} depends on {package}, but doesn't declare it as a build dependency. \
-                        If {version_id} is a first-party package, consider adding {package} to its `build-system.requires`. \
-                        Otherwise, `uv pip install {package}` into the environment and re-run with `--no-build-isolation`.",
-                    package = package, version_id = self.version_id
-                )
-            }
-        }
-    }
-}
-
-impl Error {
-    fn from_command_output(
-        message: String,
-        output: &PythonRunnerOutput,
-        level: BuildOutput,
-        version_id: impl Into<String>,
-    ) -> Self {
-        // In the cases I've seen it was the 5th and 3rd last line (see test case), 10 seems like a reasonable cutoff.
-        let missing_library = output.stderr.iter().rev().take(10).find_map(|line| {
-            if let Some((_, [header])) = MISSING_HEADER_RE_GCC
-                .captures(line.trim())
-                .or(MISSING_HEADER_RE_CLANG.captures(line.trim()))
-                .or(MISSING_HEADER_RE_MSVC.captures(line.trim()))
-                .map(|c| c.extract())
-            {
-                Some(MissingLibrary::Header(header.to_string()))
-            } else if let Some((_, [library])) =
-                LD_NOT_FOUND_RE.captures(line.trim()).map(|c| c.extract())
-            {
-                Some(MissingLibrary::Linker(library.to_string()))
-            } else if WHEEL_NOT_FOUND_RE.is_match(line.trim()) {
-                Some(MissingLibrary::PythonPackage("wheel".to_string()))
-            } else if TORCH_NOT_FOUND_RE.is_match(line.trim()) {
-                Some(MissingLibrary::PythonPackage("torch".to_string()))
-            } else {
-                None
-            }
-        });
-
-        if let Some(missing_library) = missing_library {
-            return match level {
-                BuildOutput::Stderr => Self::MissingHeader {
-                    message,
-                    exit_code: output.status,
-                    missing_header_cause: MissingHeaderCause {
-                        missing_library,
-                        version_id: version_id.into(),
-                    },
-                },
-                BuildOutput::Debug => Self::MissingHeaderOutput {
-                    message,
-                    exit_code: output.status,
-                    stdout: output.stdout.iter().join("\n"),
-                    stderr: output.stderr.iter().join("\n"),
-                    missing_header_cause: MissingHeaderCause {
-                        missing_library,
-                        version_id: version_id.into(),
-                    },
-                },
-            };
-        }
-
-        match level {
-            BuildOutput::Stderr => Self::BuildBackend {
-                message,
-                exit_code: output.status,
-            },
-            BuildOutput::Debug => Self::BuildBackendOutput {
-                message,
-                exit_code: output.status,
-                stdout: output.stdout.iter().join("\n"),
-                stderr: output.stderr.iter().join("\n"),
-            },
-        }
-    }
-}
-
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
-pub enum Printer {
-    /// Send the build backend output to `stderr`.
-    Stderr,
-    /// Send the build backend output to `tracing`.
-    Debug,
-}
-
-impl From<BuildOutput> for Printer {
-    fn from(output: BuildOutput) -> Self {
-        match output {
-            BuildOutput::Stderr => Self::Stderr,
-            BuildOutput::Debug => Self::Debug,
-        }
-    }
-}
-
-impl Write for Printer {
-    fn write_str(&mut self, s: &str) -> std::fmt::Result {
-        match self {
-            Self::Stderr => {
-                anstream::eprintln!("{s}");
-            }
-            Self::Debug => {
-                debug!("{s}");
-            }
-        }
-        Ok(())
-    }
-}
-
 /// A `pyproject.toml` as specified in PEP 517.
 #[derive(Deserialize, Debug, Clone, PartialEq, Eq)]
 #[serde(rename_all = "kebab-case")]
@@ -1166,164 +943,33 @@ impl PythonRunner {
     }
 }
 
-#[cfg(test)]
-mod test {
-    use std::process::ExitStatus;
+#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+pub enum Printer {
+    /// Send the build backend output to `stderr`.
+    Stderr,
+    /// Send the build backend output to `tracing`.
+    Debug,
+}
 
-    use crate::{Error, PythonRunnerOutput};
-    use indoc::indoc;
-    use uv_configuration::BuildOutput;
-
-    #[test]
-    fn missing_header() {
-        let output = PythonRunnerOutput {
-            status: ExitStatus::default(), // This is wrong but `from_raw` is platform-gated.
-            stdout: indoc!(r"
-                running bdist_wheel
-                running build
-                [...]
-                creating build/temp.linux-x86_64-cpython-39/pygraphviz
-                gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DOPENSSL_NO_SSL3 -fPIC -DSWIG_PYTHON_STRICT_BYTE_CHAR -I/tmp/.tmpy6vVes/.venv/include -I/home/konsti/.pyenv/versions/3.9.18/include/python3.9 -c pygraphviz/graphviz_wrap.c -o build/temp.linux-x86_64-cpython-39/pygraphviz/graphviz_wrap.o
-                "
-            ).lines().map(ToString::to_string).collect(),
-            stderr: indoc!(r#"
-                warning: no files found matching '*.png' under directory 'doc'
-                warning: no files found matching '*.txt' under directory 'doc'
-                [...]
-                no previously-included directories found matching 'doc/build'
-                pygraphviz/graphviz_wrap.c:3020:10: fatal error: graphviz/cgraph.h: No such file or directory
-                 3020 | #include "graphviz/cgraph.h"
-                      |          ^~~~~~~~~~~~~~~~~~~
-                compilation terminated.
-                error: command '/usr/bin/gcc' failed with exit code 1
-                "#
-            ).lines().map(ToString::to_string).collect(),
-        };
-
-        let err = Error::from_command_output(
-            "Failed building wheel through setup.py".to_string(),
-            &output,
-            BuildOutput::Debug,
-            "pygraphviz-1.11",
-        );
-        assert!(matches!(err, Error::MissingHeaderOutput { .. }));
-        // Unix uses exit status, Windows uses exit code.
-        let formatted = err.to_string().replace("exit status: ", "exit code: ");
-        insta::assert_snapshot!(formatted, @r###"
-        Failed building wheel through setup.py with exit code: 0
-        --- stdout:
-        running bdist_wheel
-        running build
-        [...]
-        creating build/temp.linux-x86_64-cpython-39/pygraphviz
-        gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -DOPENSSL_NO_SSL3 -fPIC -DSWIG_PYTHON_STRICT_BYTE_CHAR -I/tmp/.tmpy6vVes/.venv/include -I/home/konsti/.pyenv/versions/3.9.18/include/python3.9 -c pygraphviz/graphviz_wrap.c -o build/temp.linux-x86_64-cpython-39/pygraphviz/graphviz_wrap.o
-        --- stderr:
-        warning: no files found matching '*.png' under directory 'doc'
-        warning: no files found matching '*.txt' under directory 'doc'
-        [...]
-        no previously-included directories found matching 'doc/build'
-        pygraphviz/graphviz_wrap.c:3020:10: fatal error: graphviz/cgraph.h: No such file or directory
-         3020 | #include "graphviz/cgraph.h"
-              |          ^~~~~~~~~~~~~~~~~~~
-        compilation terminated.
-        error: command '/usr/bin/gcc' failed with exit code 1
-        ---
-        "###);
-        insta::assert_snapshot!(
-            std::error::Error::source(&err).unwrap(),
-            @r###"This error likely indicates that you need to install a library that provides "graphviz/cgraph.h" for pygraphviz-1.11"###
-        );
-    }
-
-    #[test]
-    fn missing_linker_library() {
-        let output = PythonRunnerOutput {
-            status: ExitStatus::default(), // This is wrong but `from_raw` is platform-gated.
-            stdout: Vec::new(),
-            stderr: indoc!(
-                r"
-               1099 |     n = strlen(p);
-                    |         ^~~~~~~~~
-               /usr/bin/ld: cannot find -lncurses: No such file or directory
-               collect2: error: ld returned 1 exit status
-               error: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1"
-            )
-            .lines()
-            .map(ToString::to_string)
-            .collect(),
-        };
-
-        let err = Error::from_command_output(
-            "Failed building wheel through setup.py".to_string(),
-            &output,
-            BuildOutput::Debug,
-            "pygraphviz-1.11",
-        );
-        assert!(matches!(err, Error::MissingHeaderOutput { .. }));
-        // Unix uses exit status, Windows uses exit code.
-        let formatted = err.to_string().replace("exit status: ", "exit code: ");
-        insta::assert_snapshot!(formatted, @r###"
-        Failed building wheel through setup.py with exit code: 0
-        --- stdout:
-
-        --- stderr:
-        1099 |     n = strlen(p);
-             |         ^~~~~~~~~
-        /usr/bin/ld: cannot find -lncurses: No such file or directory
-        collect2: error: ld returned 1 exit status
-        error: command '/usr/bin/x86_64-linux-gnu-gcc' failed with exit code 1
-        ---
-        "###);
-        insta::assert_snapshot!(
-            std::error::Error::source(&err).unwrap(),
-            @"This error likely indicates that you need to install the library that provides a shared library for ncurses for pygraphviz-1.11 (e.g. libncurses-dev)"
-        );
-    }
-
-    #[test]
-    fn missing_wheel_package() {
-        let output = PythonRunnerOutput {
-            status: ExitStatus::default(), // This is wrong but `from_raw` is platform-gated.
-            stdout: Vec::new(),
-            stderr: indoc!(
-                r"
-            usage: setup.py [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
-               or: setup.py --help [cmd1 cmd2 ...]
-               or: setup.py --help-commands
-               or: setup.py cmd --help
-
-            error: invalid command 'bdist_wheel'"
-            )
-            .lines()
-            .map(ToString::to_string)
-            .collect(),
-        };
-
-        let err = Error::from_command_output(
-            "Failed building wheel through setup.py".to_string(),
-            &output,
-            BuildOutput::Debug,
-            "pygraphviz-1.11",
-        );
-        assert!(matches!(err, Error::MissingHeaderOutput { .. }));
-        // Unix uses exit status, Windows uses exit code.
-        let formatted = err.to_string().replace("exit status: ", "exit code: ");
-        insta::assert_snapshot!(formatted, @r###"
-        Failed building wheel through setup.py with exit code: 0
-        --- stdout:
-
-        --- stderr:
-        usage: setup.py [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
-           or: setup.py --help [cmd1 cmd2 ...]
-           or: setup.py --help-commands
-           or: setup.py cmd --help
-
-        error: invalid command 'bdist_wheel'
-        ---
-        "###);
-        insta::assert_snapshot!(
-            std::error::Error::source(&err).unwrap(),
-            @"This error likely indicates that pygraphviz-1.11 depends on wheel, but doesn't declare it as a build dependency. If pygraphviz-1.11 is a first-party package, consider adding wheel to its `build-system.requires`. Otherwise, `uv pip install wheel` into the environment and re-run with `--no-build-isolation`."
-        );
+impl From<BuildOutput> for Printer {
+    fn from(output: BuildOutput) -> Self {
+        match output {
+            BuildOutput::Stderr => Self::Stderr,
+            BuildOutput::Debug => Self::Debug,
+        }
+    }
+}
+
+impl Write for Printer {
+    fn write_str(&mut self, s: &str) -> std::fmt::Result {
+        match self {
+            Self::Stderr => {
+                anstream::eprintln!("{s}");
+            }
+            Self::Debug => {
+                debug!("{s}");
+            }
+        }
+        Ok(())
     }
 }