diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9088bc3..4fe500b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # CHANGELOG
 
+## Unreleased
+
+- Squirrel will now pick files under a project's `test` and `dev` directories.
+  ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
+
 ## 4.0.1 - 2025-07-14
 
 - Fixed a bug where using numeric types in a query would result in runtime
diff --git a/manifest.toml b/manifest.toml
index 91d0b86..9990bfd 100644
--- a/manifest.toml
+++ b/manifest.toml
@@ -4,7 +4,7 @@
 packages = [
   { name = "argv", version = "1.0.2", build_tools = ["gleam"], requirements = [], otp_app = "argv", source = "hex", outer_checksum = "BA1FF0929525DEBA1CE67256E5ADF77A7CDDFE729E3E3F57A5BDCAA031DED09D" },
   { name = "backoff", version = "1.1.6", build_tools = ["rebar3"], requirements = [], otp_app = "backoff", source = "hex", outer_checksum = "CF0CFFF8995FB20562F822E5CC47D8CCF664C5ECDC26A684CBE85C225F9D7C39" },
-  { name = "birdie", version = "1.3.1", build_tools = ["gleam"], requirements = ["argv", "edit_distance", "filepath", "glance", "gleam_community_ansi", "gleam_stdlib", "justin", "rank", "simplifile", "term_size", "trie_again"], otp_app = "birdie", source = "hex", outer_checksum = "F811C9EDAF920EF48597A26E788907AAF80D9239A5E8C8CCFBD0DD1BB10184D7" },
+  { name = "birdie", version = "1.3.2", build_tools = ["gleam"], requirements = ["argv", "edit_distance", "filepath", "glance", "gleam_community_ansi", "gleam_stdlib", "justin", "rank", "simplifile", "term_size", "trie_again"], otp_app = "birdie", source = "hex", outer_checksum = "3D3980E497777C74068F3509564AF19E1EC4D42B3CC833E998177B5CD0ECDEF9" },
   { name = "edit_distance", version = "2.0.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "edit_distance", source = "hex", outer_checksum = "A1E485C69A70210223E46E63985FA1008B8B2DDA9848B7897469171B29020C05" },
   { name = "envoy", version = "1.0.2", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "envoy", source = "hex", outer_checksum = "95FD059345AA982E89A0B6E2A3BF1CF43E17A7048DCD85B5B65D3B9E4E39D359" },
   { name = "eval", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "eval", source = "hex", outer_checksum = "264DAF4B49DF807F303CA4A4E4EBC012070429E40BE384C58FE094C4958F9BDA" },
@@ -20,8 +20,8 @@ packages = [
   { name = "gleam_otp", version = "1.0.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "gleam_otp", source = "hex", outer_checksum = "7020E652D18F9ABAC9C877270B14160519FA0856EE80126231C505D719AD68DA" },
   { name = "gleam_regexp", version = "1.1.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_regexp", source = "hex", outer_checksum = "9C215C6CA84A5B35BB934A9B61A9A306EC743153BE2B0425A0D032E477B062A9" },
   { name = "gleam_stdlib", version = "0.62.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "DC8872BC0B8550F6E22F0F698CFE7F1E4BDA7312FDEB40D6C3F44C5B706C8310" },
-  { name = "gleam_time", version = "1.3.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_time", source = "hex", outer_checksum = "F9AB61CE910F3071B136E1C8E214A46C406734F710D3AF75C99B00DA785902A2" },
-  { name = "gleeunit", version = "1.6.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "63022D81C12C17B7F1A60E029964E830A4CBD846BBC6740004FC1F1031AE0326" },
+  { name = "gleam_time", version = "1.4.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_time", source = "hex", outer_checksum = "DCDDC040CE97DA3D2A925CDBBA08D8A78681139745754A83998641C8A3F6587E" },
+  { name = "gleeunit", version = "1.6.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "FDC68A8C492B1E9B429249062CD9BAC9B5538C6FBF584817205D0998C42E1DAC" },
   { name = "glexer", version = "2.2.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "glexer", source = "hex", outer_checksum = "5C235CBDF4DA5203AD5EAB1D6D8B456ED8162C5424FE2309CFFB7EF438B7C269" },
   { name = "justin", version = "1.0.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "justin", source = "hex", outer_checksum = "7FA0C6DB78640C6DC5FBFD59BF3456009F3F8B485BF6825E97E1EB44E9A1E2CD" },
   { name = "mug", version = "3.0.0", build_tools = ["gleam"], requirements = ["gleam_erlang", "gleam_stdlib"], otp_app = "mug", source = "hex", outer_checksum = "49AD2B71690C6A615453D272300951C4BDE19FBF55B167D9C951F5CD89FEC820" },
diff --git a/src/squirrel.gleam b/src/squirrel.gleam
index 60bcbcb..0511743 100644
--- a/src/squirrel.gleam
+++ b/src/squirrel.gleam
@@ -86,6 +86,8 @@ pub fn main() {
     Ok(mode), Ok(options) -> {
       let generated_queries =
         walk(project.src())
+        |> dict.merge(walk(project.test_()))
+        |> dict.merge(walk(project.dev()))
         |> generate_queries(options)
 
       let #(report, status_code) = case mode {
@@ -291,7 +293,11 @@ fn walk(from: String) -> Dict(String, List(String)) {
     }
 
     _ -> {
-      let assert Ok(files) = simplifile.read_directory(from)
+      let files = case simplifile.read_directory(from) {
+        Ok(files) -> files
+        Error(simplifile.Enoent) -> []
+        Error(_) -> panic as { "couldn't read directory: " <> from }
+      }
       let directories = {
         use file <- list.filter_map(files)
         let file_name = filepath.join(from, file)
diff --git a/src/squirrel/internal/project.gleam b/src/squirrel/internal/project.gleam
index 3bb0cfb..83fe27e 100644
--- a/src/squirrel/internal/project.gleam
+++ b/src/squirrel/internal/project.gleam
@@ -32,6 +32,22 @@ pub fn src() -> String {
   filepath.join(root(), "src")
 }
 
+/// Finds the path of the project's `test` directory.
+/// This recursively walks up from the current directory until it finds a
+/// `gleam.toml` and builds it from there.
+///
+pub fn test_() -> String {
+  filepath.join(root(), "test")
+}
+
+/// Finds the path of the project's `dev` directory.
+/// This recursively walks up from the current directory until it finds a
+/// `gleam.toml` and builds it from there.
+///
+pub fn dev() -> String {
+  filepath.join(root(), "dev")
+}
+
 /// Finds the path leading to the project's root folder. This recursively walks
 /// up from the current directory until it finds a `gleam.toml`.
 ///