diff --git a/src/commands.rs b/src/commands.rs
index 1d1947426b..afff463905 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -13,13 +13,12 @@ use serde::Serialize;
 use crate::autofix::fixer;
 use crate::checks::{CheckCode, CheckKind};
 use crate::cli::Overrides;
-use crate::fs::collect_python_files;
 use crate::iterators::par_iter;
 use crate::linter::{add_noqa_to_path, autoformat_path, lint_path, lint_stdin, Diagnostics};
 use crate::message::Message;
 use crate::resolver::Strategy;
 use crate::settings::types::SerializationFormat;
-use crate::{Configuration, Settings};
+use crate::{resolver, Configuration, Settings};
 
 /// Run the linter over a collection of files.
 pub fn run(
@@ -32,7 +31,7 @@ pub fn run(
 ) -> Diagnostics {
     // Collect all the files to check.
     let start = Instant::now();
-    let (paths, resolver) = collect_python_files(files, strategy, overrides, defaults);
+    let (paths, resolver) = resolver::resolve_python_files(files, strategy, overrides, defaults);
     let duration = start.elapsed();
     debug!("Identified files to lint in: {:?}", duration);
 
@@ -114,7 +113,7 @@ pub fn add_noqa(
 ) -> usize {
     // Collect all the files to check.
     let start = Instant::now();
-    let (paths, resolver) = collect_python_files(files, strategy, overrides, defaults);
+    let (paths, resolver) = resolver::resolve_python_files(files, strategy, overrides, defaults);
     let duration = start.elapsed();
     debug!("Identified files to lint in: {:?}", duration);
 
@@ -149,7 +148,7 @@ pub fn autoformat(
 ) -> usize {
     // Collect all the files to format.
     let start = Instant::now();
-    let (paths, resolver) = collect_python_files(files, strategy, overrides, defaults);
+    let (paths, resolver) = resolver::resolve_python_files(files, strategy, overrides, defaults);
     let duration = start.elapsed();
     debug!("Identified files to lint in: {:?}", duration);
 
@@ -189,7 +188,7 @@ pub fn show_files(
     overrides: &Overrides,
 ) {
     // Collect all files in the hierarchy.
-    let (paths, _resolver) = collect_python_files(files, strategy, overrides, default);
+    let (paths, _resolver) = resolver::resolve_python_files(files, strategy, overrides, default);
 
     // Print the list of files.
     for entry in paths
diff --git a/src/fs.rs b/src/fs.rs
index c252101e73..83ec117a25 100644
--- a/src/fs.rs
+++ b/src/fs.rs
@@ -5,19 +5,13 @@ use std::path::{Path, PathBuf};
 
 use anyhow::{anyhow, Result};
 use globset::GlobMatcher;
-use log::{debug, error};
 use path_absolutize::{path_dedot, Absolutize};
 use rustc_hash::FxHashSet;
-use walkdir::{DirEntry, WalkDir};
 
 use crate::checks::CheckCode;
-use crate::cli::Overrides;
-use crate::resolver;
-use crate::resolver::{Resolver, Strategy};
-use crate::settings::Settings;
 
 /// Extract the absolute path and basename (as strings) from a Path.
-fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
+pub fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
     let file_path = path
         .to_str()
         .ok_or_else(|| anyhow!("Unable to parse filename: {:?}", path))?;
@@ -29,109 +23,7 @@ fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
     Ok((file_path, file_basename))
 }
 
-fn is_excluded(file_path: &str, file_basename: &str, exclude: &globset::GlobSet) -> bool {
-    exclude.is_match(file_path) || exclude.is_match(file_basename)
-}
-
-fn is_included(path: &Path) -> bool {
-    path.extension()
-        .map_or(false, |ext| ext == "py" || ext == "pyi")
-}
-
-/// Find all Python (`.py` and `.pyi` files) in a set of `Path`.
-pub fn collect_python_files<'a>(
-    paths: &'a [PathBuf],
-    strategy: &Strategy,
-    overrides: &'a Overrides,
-    default: &'a Settings,
-) -> (Vec<Result<DirEntry, walkdir::Error>>, Resolver) {
-    let mut files = Vec::new();
-    let mut resolver = Resolver::default();
-    for path in paths {
-        let (files_in_path, file_resolver) =
-            python_files_in_path(path, strategy, overrides, default);
-        files.extend(files_in_path);
-        resolver.merge(file_resolver);
-    }
-    (files, resolver)
-}
-
-/// Find all Python (`.py` and `.pyi` files) in a given `Path`.
-fn python_files_in_path<'a>(
-    path: &'a Path,
-    strategy: &Strategy,
-    overrides: &'a Overrides,
-    default: &'a Settings,
-) -> (Vec<Result<DirEntry, walkdir::Error>>, Resolver) {
-    let path = normalize_path(path);
-
-    // Search for `pyproject.toml` files in all parent directories.
-    let mut resolver = Resolver::default();
-    for path in path.ancestors() {
-        if path.is_dir() {
-            let pyproject = path.join("pyproject.toml");
-            if pyproject.is_file() {
-                match resolver::settings_for_path(&pyproject, overrides) {
-                    Ok((root, settings)) => resolver.add(root, settings),
-                    Err(err) => error!("Failed to read settings: {err}"),
-                }
-            }
-        }
-    }
-
-    // Collect all Python files.
-    let files: Vec<Result<DirEntry, walkdir::Error>> = WalkDir::new(path)
-        .into_iter()
-        .filter_entry(|entry| {
-            // Search for the `pyproject.toml` file in this directory, before we visit any
-            // of its contents.
-            if entry.file_type().is_dir() {
-                let pyproject = entry.path().join("pyproject.toml");
-                if pyproject.is_file() {
-                    match resolver::settings_for_path(&pyproject, overrides) {
-                        Ok((root, settings)) => resolver.add(root, settings),
-                        Err(err) => error!("Failed to read settings: {err}"),
-                    }
-                }
-            }
-
-            let path = entry.path();
-            let settings = resolver.resolve(path, strategy).unwrap_or(default);
-            match extract_path_names(path) {
-                Ok((file_path, file_basename)) => {
-                    if !settings.exclude.is_empty()
-                        && is_excluded(file_path, file_basename, &settings.exclude)
-                    {
-                        debug!("Ignored path via `exclude`: {:?}", path);
-                        false
-                    } else if !settings.extend_exclude.is_empty()
-                        && is_excluded(file_path, file_basename, &settings.extend_exclude)
-                    {
-                        debug!("Ignored path via `extend-exclude`: {:?}", path);
-                        false
-                    } else {
-                        true
-                    }
-                }
-                Err(e) => {
-                    debug!("Ignored path due to error in parsing: {:?}: {}", path, e);
-                    true
-                }
-            }
-        })
-        .filter(|entry| {
-            entry.as_ref().map_or(true, |entry| {
-                (entry.depth() == 0 || is_included(entry.path()))
-                    && !entry.file_type().is_dir()
-                    && !(entry.file_type().is_symlink() && entry.path().is_dir())
-            })
-        })
-        .collect::<Vec<_>>();
-
-    (files, resolver)
-}
-
-/// Create tree set with codes matching the pattern/code pairs.
+/// Create a set with codes matching the pattern/code pairs.
 pub(crate) fn ignores_from_path<'a>(
     path: &Path,
     pattern_code_pairs: &'a [(GlobMatcher, GlobMatcher, FxHashSet<CheckCode>)],
@@ -179,114 +71,3 @@ pub(crate) fn read_file(path: &Path) -> Result<String> {
     buf_reader.read_to_string(&mut contents)?;
     Ok(contents)
 }
-
-#[cfg(test)]
-mod tests {
-    use std::path::Path;
-
-    use anyhow::Result;
-    use globset::GlobSet;
-    use path_absolutize::Absolutize;
-
-    use crate::fs::{extract_path_names, is_excluded, is_included};
-    use crate::settings::types::FilePattern;
-
-    #[test]
-    fn inclusions() {
-        let path = Path::new("foo/bar/baz.py").absolutize().unwrap();
-        assert!(is_included(&path));
-
-        let path = Path::new("foo/bar/baz.pyi").absolutize().unwrap();
-        assert!(is_included(&path));
-
-        let path = Path::new("foo/bar/baz.js").absolutize().unwrap();
-        assert!(!is_included(&path));
-
-        let path = Path::new("foo/bar/baz").absolutize().unwrap();
-        assert!(!is_included(&path));
-    }
-
-    fn make_exclusion(file_pattern: FilePattern, project_root: &Path) -> GlobSet {
-        let mut builder = globset::GlobSetBuilder::new();
-        file_pattern.add_to(&mut builder, project_root).unwrap();
-        builder.build().unwrap()
-    }
-
-    #[test]
-    fn exclusions() -> Result<()> {
-        let project_root = Path::new("/tmp/");
-
-        let path = Path::new("foo").absolutize_from(project_root).unwrap();
-        let exclude = FilePattern::User("foo".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, project_root)
-        ));
-
-        let path = Path::new("foo/bar").absolutize_from(project_root).unwrap();
-        let exclude = FilePattern::User("bar".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, project_root)
-        ));
-
-        let path = Path::new("foo/bar/baz.py")
-            .absolutize_from(project_root)
-            .unwrap();
-        let exclude = FilePattern::User("baz.py".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, project_root)
-        ));
-
-        let path = Path::new("foo/bar").absolutize_from(project_root).unwrap();
-        let exclude = FilePattern::User("foo/bar".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, project_root)
-        ));
-
-        let path = Path::new("foo/bar/baz.py")
-            .absolutize_from(project_root)
-            .unwrap();
-        let exclude = FilePattern::User("foo/bar/baz.py".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, project_root)
-        ));
-
-        let path = Path::new("foo/bar/baz.py")
-            .absolutize_from(project_root)
-            .unwrap();
-        let exclude = FilePattern::User("foo/bar/*.py".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, project_root)
-        ));
-
-        let path = Path::new("foo/bar/baz.py")
-            .absolutize_from(project_root)
-            .unwrap();
-        let exclude = FilePattern::User("baz".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(!is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, project_root)
-        ));
-
-        Ok(())
-    }
-}
diff --git a/src/resolver.rs b/src/resolver.rs
index fa181226f9..42ede8b504 100644
--- a/src/resolver.rs
+++ b/src/resolver.rs
@@ -1,11 +1,15 @@
-//! Discover and resolve `Settings` from the filesystem hierarchy.
+//! Discover Python files, and their corresponding `Settings`, from the
+//! filesystem.
 
 use std::collections::BTreeMap;
 use std::path::{Path, PathBuf};
 
 use anyhow::{anyhow, Result};
+use log::{debug, error};
+use walkdir::{DirEntry, WalkDir};
 
 use crate::cli::Overrides;
+use crate::fs;
 use crate::settings::configuration::Configuration;
 use crate::settings::{pyproject, Settings};
 
@@ -54,3 +58,220 @@ pub fn settings_for_path(pyproject: &Path, overrides: &Overrides) -> Result<(Pat
     let settings = Settings::from_configuration(configuration, &project_root)?;
     Ok((project_root, settings))
 }
+
+/// Return `true` if the given file should be ignored based on the exclusion
+/// criteria.
+fn is_excluded(file_path: &str, file_basename: &str, exclude: &globset::GlobSet) -> bool {
+    exclude.is_match(file_path) || exclude.is_match(file_basename)
+}
+
+/// Return `true` if the `Path` appears to be that of a Python file.
+fn is_python_file(path: &Path) -> bool {
+    path.extension()
+        .map_or(false, |ext| ext == "py" || ext == "pyi")
+}
+
+/// Find all Python (`.py` and `.pyi` files) in a set of `Path`.
+pub fn resolve_python_files<'a>(
+    paths: &'a [PathBuf],
+    strategy: &Strategy,
+    overrides: &'a Overrides,
+    default: &'a Settings,
+) -> (Vec<Result<DirEntry, walkdir::Error>>, Resolver) {
+    let mut files = Vec::new();
+    let mut resolver = Resolver::default();
+    for path in paths {
+        let (files_in_path, file_resolver) =
+            python_files_in_path(path, strategy, overrides, default);
+        files.extend(files_in_path);
+        resolver.merge(file_resolver);
+    }
+    (files, resolver)
+}
+
+/// Find all Python (`.py` and `.pyi` files) in a given `Path`.
+fn python_files_in_path<'a>(
+    path: &'a Path,
+    strategy: &Strategy,
+    overrides: &'a Overrides,
+    default: &'a Settings,
+) -> (Vec<Result<DirEntry, walkdir::Error>>, Resolver) {
+    let path = fs::normalize_path(path);
+
+    // Search for `pyproject.toml` files in all parent directories.
+    let mut resolver = Resolver::default();
+    for path in path.ancestors() {
+        if path.is_dir() {
+            let pyproject = path.join("pyproject.toml");
+            if pyproject.is_file() {
+                match settings_for_path(&pyproject, overrides) {
+                    Ok((root, settings)) => resolver.add(root, settings),
+                    Err(err) => error!("Failed to read settings: {err}"),
+                }
+            }
+        }
+    }
+
+    // Collect all Python files.
+    let files: Vec<Result<DirEntry, walkdir::Error>> = WalkDir::new(path)
+        .into_iter()
+        .filter_entry(|entry| {
+            // Search for the `pyproject.toml` file in this directory, before we visit any
+            // of its contents.
+            if entry.file_type().is_dir() {
+                let pyproject = entry.path().join("pyproject.toml");
+                if pyproject.is_file() {
+                    match settings_for_path(&pyproject, overrides) {
+                        Ok((root, settings)) => resolver.add(root, settings),
+                        Err(err) => error!("Failed to read settings: {err}"),
+                    }
+                }
+            }
+
+            let path = entry.path();
+            let settings = resolver.resolve(path, strategy).unwrap_or(default);
+            match fs::extract_path_names(path) {
+                Ok((file_path, file_basename)) => {
+                    if !settings.exclude.is_empty()
+                        && is_excluded(file_path, file_basename, &settings.exclude)
+                    {
+                        debug!("Ignored path via `exclude`: {:?}", path);
+                        false
+                    } else if !settings.extend_exclude.is_empty()
+                        && is_excluded(file_path, file_basename, &settings.extend_exclude)
+                    {
+                        debug!("Ignored path via `extend-exclude`: {:?}", path);
+                        false
+                    } else {
+                        true
+                    }
+                }
+                Err(e) => {
+                    debug!("Ignored path due to error in parsing: {:?}: {}", path, e);
+                    true
+                }
+            }
+        })
+        .filter(|entry| {
+            entry.as_ref().map_or(true, |entry| {
+                (entry.depth() == 0 || is_python_file(entry.path()))
+                    && !entry.file_type().is_dir()
+                    && !(entry.file_type().is_symlink() && entry.path().is_dir())
+            })
+        })
+        .collect::<Vec<_>>();
+
+    (files, resolver)
+}
+
+#[cfg(test)]
+mod tests {
+    use std::path::Path;
+
+    use anyhow::Result;
+    use globset::GlobSet;
+    use path_absolutize::Absolutize;
+
+    use crate::fs;
+    use crate::resolver::{is_excluded, is_python_file};
+    use crate::settings::types::FilePattern;
+
+    #[test]
+    fn inclusions() {
+        let path = Path::new("foo/bar/baz.py").absolutize().unwrap();
+        assert!(is_python_file(&path));
+
+        let path = Path::new("foo/bar/baz.pyi").absolutize().unwrap();
+        assert!(is_python_file(&path));
+
+        let path = Path::new("foo/bar/baz.js").absolutize().unwrap();
+        assert!(!is_python_file(&path));
+
+        let path = Path::new("foo/bar/baz").absolutize().unwrap();
+        assert!(!is_python_file(&path));
+    }
+
+    fn make_exclusion(file_pattern: FilePattern, project_root: &Path) -> GlobSet {
+        let mut builder = globset::GlobSetBuilder::new();
+        file_pattern.add_to(&mut builder, project_root).unwrap();
+        builder.build().unwrap()
+    }
+
+    #[test]
+    fn exclusions() -> Result<()> {
+        let project_root = Path::new("/tmp/");
+
+        let path = Path::new("foo").absolutize_from(project_root).unwrap();
+        let exclude = FilePattern::User("foo".to_string());
+        let (file_path, file_basename) = fs::extract_path_names(&path)?;
+        assert!(is_excluded(
+            file_path,
+            file_basename,
+            &make_exclusion(exclude, project_root)
+        ));
+
+        let path = Path::new("foo/bar").absolutize_from(project_root).unwrap();
+        let exclude = FilePattern::User("bar".to_string());
+        let (file_path, file_basename) = fs::extract_path_names(&path)?;
+        assert!(is_excluded(
+            file_path,
+            file_basename,
+            &make_exclusion(exclude, project_root)
+        ));
+
+        let path = Path::new("foo/bar/baz.py")
+            .absolutize_from(project_root)
+            .unwrap();
+        let exclude = FilePattern::User("baz.py".to_string());
+        let (file_path, file_basename) = fs::extract_path_names(&path)?;
+        assert!(is_excluded(
+            file_path,
+            file_basename,
+            &make_exclusion(exclude, project_root)
+        ));
+
+        let path = Path::new("foo/bar").absolutize_from(project_root).unwrap();
+        let exclude = FilePattern::User("foo/bar".to_string());
+        let (file_path, file_basename) = fs::extract_path_names(&path)?;
+        assert!(is_excluded(
+            file_path,
+            file_basename,
+            &make_exclusion(exclude, project_root)
+        ));
+
+        let path = Path::new("foo/bar/baz.py")
+            .absolutize_from(project_root)
+            .unwrap();
+        let exclude = FilePattern::User("foo/bar/baz.py".to_string());
+        let (file_path, file_basename) = fs::extract_path_names(&path)?;
+        assert!(is_excluded(
+            file_path,
+            file_basename,
+            &make_exclusion(exclude, project_root)
+        ));
+
+        let path = Path::new("foo/bar/baz.py")
+            .absolutize_from(project_root)
+            .unwrap();
+        let exclude = FilePattern::User("foo/bar/*.py".to_string());
+        let (file_path, file_basename) = fs::extract_path_names(&path)?;
+        assert!(is_excluded(
+            file_path,
+            file_basename,
+            &make_exclusion(exclude, project_root)
+        ));
+
+        let path = Path::new("foo/bar/baz.py")
+            .absolutize_from(project_root)
+            .unwrap();
+        let exclude = FilePattern::User("baz".to_string());
+        let (file_path, file_basename) = fs::extract_path_names(&path)?;
+        assert!(!is_excluded(
+            file_path,
+            file_basename,
+            &make_exclusion(exclude, project_root)
+        ));
+
+        Ok(())
+    }
+}