diff --git a/crates/chat_panel/Cargo.toml b/crates/chat_panel/Cargo.toml
index 9b7d3664d7..7f34579c87 100644
--- a/crates/chat_panel/Cargo.toml
+++ b/crates/chat_panel/Cargo.toml
@@ -3,6 +3,9 @@ name = "chat_panel"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/chat_panel.rs"
+
 [dependencies]
 client = { path = "../client" }
 editor = { path = "../editor" }
diff --git a/crates/chat_panel/src/lib.rs b/crates/chat_panel/src/chat_panel.rs
similarity index 100%
rename from crates/chat_panel/src/lib.rs
rename to crates/chat_panel/src/chat_panel.rs
diff --git a/crates/client/Cargo.toml b/crates/client/Cargo.toml
index 455e6a00fe..bec27f84c5 100644
--- a/crates/client/Cargo.toml
+++ b/crates/client/Cargo.toml
@@ -3,6 +3,9 @@ name = "client"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/client.rs"
+
 [features]
 test-support = ["rpc/test-support"]
 
diff --git a/crates/client/src/lib.rs b/crates/client/src/client.rs
similarity index 100%
rename from crates/client/src/lib.rs
rename to crates/client/src/client.rs
diff --git a/crates/clock/Cargo.toml b/crates/clock/Cargo.toml
index 3e5d84935d..7ddb64872a 100644
--- a/crates/clock/Cargo.toml
+++ b/crates/clock/Cargo.toml
@@ -3,6 +3,9 @@ name = "clock"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/clock.rs"
+
 [dependencies]
 smallvec = { version = "1.6", features = ["union"] }
 rpc = { path = "../rpc" }
diff --git a/crates/clock/src/lib.rs b/crates/clock/src/clock.rs
similarity index 100%
rename from crates/clock/src/lib.rs
rename to crates/clock/src/clock.rs
diff --git a/crates/collections/Cargo.toml b/crates/collections/Cargo.toml
index b0b1a8bd38..8ca3ccd4e9 100644
--- a/crates/collections/Cargo.toml
+++ b/crates/collections/Cargo.toml
@@ -3,6 +3,9 @@ name = "collections"
 version = "0.1.0"
 edition = "2021"
 
+[lib]
+path = "src/collections.rs"
+
 [features]
 test-support = ["seahash"]
 
diff --git a/crates/collections/src/lib.rs b/crates/collections/src/collections.rs
similarity index 100%
rename from crates/collections/src/lib.rs
rename to crates/collections/src/collections.rs
diff --git a/crates/contacts_panel/Cargo.toml b/crates/contacts_panel/Cargo.toml
index ffeb8e6a3d..38d0c02609 100644
--- a/crates/contacts_panel/Cargo.toml
+++ b/crates/contacts_panel/Cargo.toml
@@ -3,6 +3,9 @@ name = "contacts_panel"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/contacts_panel.rs"
+
 [dependencies]
 client = { path = "../client" }
 gpui = { path = "../gpui" }
diff --git a/crates/contacts_panel/src/lib.rs b/crates/contacts_panel/src/contacts_panel.rs
similarity index 100%
rename from crates/contacts_panel/src/lib.rs
rename to crates/contacts_panel/src/contacts_panel.rs
diff --git a/crates/editor/Cargo.toml b/crates/editor/Cargo.toml
index 3160be8be6..ed0d1b7413 100644
--- a/crates/editor/Cargo.toml
+++ b/crates/editor/Cargo.toml
@@ -3,6 +3,9 @@ name = "editor"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/editor.rs"
+
 [features]
 test-support = [
     "text/test-support",
diff --git a/crates/editor/src/lib.rs b/crates/editor/src/editor.rs
similarity index 100%
rename from crates/editor/src/lib.rs
rename to crates/editor/src/editor.rs
diff --git a/crates/file_finder/Cargo.toml b/crates/file_finder/Cargo.toml
index 81995e2e7a..521eefb6fc 100644
--- a/crates/file_finder/Cargo.toml
+++ b/crates/file_finder/Cargo.toml
@@ -3,6 +3,9 @@ name = "file_finder"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/file_finder.rs"
+
 [dependencies]
 editor = { path = "../editor" }
 fuzzy = { path = "../fuzzy" }
diff --git a/crates/file_finder/src/lib.rs b/crates/file_finder/src/file_finder.rs
similarity index 100%
rename from crates/file_finder/src/lib.rs
rename to crates/file_finder/src/file_finder.rs
diff --git a/crates/fsevent/Cargo.toml b/crates/fsevent/Cargo.toml
index 03b565cb9f..f4d1b1d04a 100644
--- a/crates/fsevent/Cargo.toml
+++ b/crates/fsevent/Cargo.toml
@@ -4,6 +4,9 @@ version = "2.0.2"
 license = "MIT"
 edition = "2018"
 
+[lib]
+path = "src/fsevent.rs"
+
 [dependencies]
 bitflags = "1"
 fsevent-sys = "3.0.2"
diff --git a/crates/fsevent/src/lib.rs b/crates/fsevent/src/fsevent.rs
similarity index 100%
rename from crates/fsevent/src/lib.rs
rename to crates/fsevent/src/fsevent.rs
diff --git a/crates/fuzzy/Cargo.toml b/crates/fuzzy/Cargo.toml
index 0a60e0973d..dec485ffe3 100644
--- a/crates/fuzzy/Cargo.toml
+++ b/crates/fuzzy/Cargo.toml
@@ -3,6 +3,9 @@ name = "fuzzy"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/fuzzy.rs"
+
 [dependencies]
 gpui = { path = "../gpui" }
 util = { path = "../util" }
diff --git a/crates/fuzzy/src/lib.rs b/crates/fuzzy/src/fuzzy.rs
similarity index 100%
rename from crates/fuzzy/src/lib.rs
rename to crates/fuzzy/src/fuzzy.rs
diff --git a/crates/go_to_line/Cargo.toml b/crates/go_to_line/Cargo.toml
index bebdcf1b40..f98b1b2ee0 100644
--- a/crates/go_to_line/Cargo.toml
+++ b/crates/go_to_line/Cargo.toml
@@ -3,6 +3,9 @@ name = "go_to_line"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/go_to_line.rs"
+
 [dependencies]
 text = { path = "../text" }
 editor = { path = "../editor" }
diff --git a/crates/go_to_line/src/lib.rs b/crates/go_to_line/src/go_to_line.rs
similarity index 100%
rename from crates/go_to_line/src/lib.rs
rename to crates/go_to_line/src/go_to_line.rs
diff --git a/crates/gpui/Cargo.toml b/crates/gpui/Cargo.toml
index dc1edc6547..7c237d48e5 100644
--- a/crates/gpui/Cargo.toml
+++ b/crates/gpui/Cargo.toml
@@ -4,6 +4,9 @@ edition = "2018"
 name = "gpui"
 version = "0.1.0"
 
+[lib]
+path = "src/gpui.rs"
+
 [features]
 test-support = ["env_logger"]
 
diff --git a/crates/gpui/src/lib.rs b/crates/gpui/src/gpui.rs
similarity index 100%
rename from crates/gpui/src/lib.rs
rename to crates/gpui/src/gpui.rs
diff --git a/crates/gpui_macros/Cargo.toml b/crates/gpui_macros/Cargo.toml
index a5d7373463..8f1c9faba5 100644
--- a/crates/gpui_macros/Cargo.toml
+++ b/crates/gpui_macros/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2018"
 
 [lib]
+path = "src/gpui_macros.rs"
 proc-macro = true
 
 [dependencies]
diff --git a/crates/gpui_macros/src/lib.rs b/crates/gpui_macros/src/gpui_macros.rs
similarity index 100%
rename from crates/gpui_macros/src/lib.rs
rename to crates/gpui_macros/src/gpui_macros.rs
diff --git a/crates/language/Cargo.toml b/crates/language/Cargo.toml
index 76659e5428..ad0f84b4dc 100644
--- a/crates/language/Cargo.toml
+++ b/crates/language/Cargo.toml
@@ -3,6 +3,9 @@ name = "language"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/language.rs"
+
 [features]
 test-support = [
     "rand",
diff --git a/crates/language/src/lib.rs b/crates/language/src/buffer.rs
similarity index 99%
rename from crates/language/src/lib.rs
rename to crates/language/src/buffer.rs
index d70ea71be1..d71662d0d9 100644
--- a/crates/language/src/lib.rs
+++ b/crates/language/src/buffer.rs
@@ -1,15 +1,7 @@
-mod highlight_map;
-mod language;
-pub mod proto;
-#[cfg(test)]
-mod tests;
-
-pub use self::{
+pub use crate::{
     highlight_map::{HighlightId, HighlightMap},
-    language::{
-        BracketPair, Grammar, Language, LanguageConfig, LanguageRegistry, LanguageServerConfig,
-        PLAIN_TEXT,
-    },
+    proto, BracketPair, Grammar, Language, LanguageConfig, LanguageRegistry, LanguageServerConfig,
+    PLAIN_TEXT,
 };
 use anyhow::{anyhow, Result};
 use clock::ReplicaId;
@@ -73,7 +65,7 @@ pub struct Buffer {
     diagnostics_update_count: usize,
     language_server: Option<LanguageServerState>,
     #[cfg(test)]
-    operations: Vec<Operation>,
+    pub(crate) operations: Vec<Operation>,
 }
 
 pub struct Snapshot {
@@ -217,7 +209,7 @@ pub struct Chunk<'a> {
     pub diagnostic: Option<DiagnosticSeverity>,
 }
 
-struct Diff {
+pub(crate) struct Diff {
     base_version: clock::Global,
     new_text: Arc<str>,
     changes: Vec<(ChangeTag, usize)>,
@@ -573,7 +565,7 @@ impl Buffer {
         self.parse_count
     }
 
-    fn syntax_tree(&self) -> Option<Tree> {
+    pub(crate) fn syntax_tree(&self) -> Option<Tree> {
         if let Some(syntax_tree) = self.syntax_tree.lock().as_mut() {
             self.interpolate_tree(syntax_tree);
             Some(syntax_tree.tree.clone())
@@ -1094,7 +1086,7 @@ impl Buffer {
             .min_by_key(|(open_range, close_range)| close_range.end - open_range.start)
     }
 
-    fn diff(&self, new_text: Arc<str>, cx: &AppContext) -> Task<Diff> {
+    pub(crate) fn diff(&self, new_text: Arc<str>, cx: &AppContext) -> Task<Diff> {
         // TODO: it would be nice to not allocate here.
         let old_text = self.text();
         let base_version = self.version();
@@ -1111,7 +1103,7 @@ impl Buffer {
         })
     }
 
-    fn apply_diff(&mut self, diff: Diff, cx: &mut ModelContext<Self>) -> bool {
+    pub(crate) fn apply_diff(&mut self, diff: Diff, cx: &mut ModelContext<Self>) -> bool {
         if self.version == diff.base_version {
             self.start_transaction(None).unwrap();
             let mut offset = 0;
@@ -1153,7 +1145,7 @@ impl Buffer {
         self.start_transaction_at(selection_set_ids, Instant::now())
     }
 
-    fn start_transaction_at(
+    pub(crate) fn start_transaction_at(
         &mut self,
         selection_set_ids: impl IntoIterator<Item = SelectionSetId>,
         now: Instant,
@@ -1169,7 +1161,7 @@ impl Buffer {
         self.end_transaction_at(selection_set_ids, Instant::now(), cx)
     }
 
-    fn end_transaction_at(
+    pub(crate) fn end_transaction_at(
         &mut self,
         selection_set_ids: impl IntoIterator<Item = SelectionSetId>,
         now: Instant,
@@ -1995,7 +1987,7 @@ fn diagnostic_ranges<'a>(
         ))
 }
 
-fn contiguous_ranges(
+pub fn contiguous_ranges(
     values: impl IntoIterator<Item = u32>,
     max_len: usize,
 ) -> impl Iterator<Item = Range<u32>> {
diff --git a/crates/language/src/language.rs b/crates/language/src/language.rs
index f8201b179b..77d01c7ecf 100644
--- a/crates/language/src/language.rs
+++ b/crates/language/src/language.rs
@@ -1,6 +1,14 @@
-use crate::HighlightMap;
+mod buffer;
+mod highlight_map;
+pub mod proto;
+#[cfg(test)]
+mod tests;
+
 use anyhow::{anyhow, Result};
+pub use buffer::Operation;
+pub use buffer::*;
 use gpui::{executor::Background, AppContext};
+use highlight_map::HighlightMap;
 use lazy_static::lazy_static;
 use lsp::LanguageServer;
 use parking_lot::Mutex;
@@ -223,56 +231,3 @@ impl LanguageServerConfig {
         )
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_select_language() {
-        let registry = LanguageRegistry {
-            languages: vec![
-                Arc::new(Language::new(
-                    LanguageConfig {
-                        name: "Rust".to_string(),
-                        path_suffixes: vec!["rs".to_string()],
-                        ..Default::default()
-                    },
-                    Some(tree_sitter_rust::language()),
-                )),
-                Arc::new(Language::new(
-                    LanguageConfig {
-                        name: "Make".to_string(),
-                        path_suffixes: vec!["Makefile".to_string(), "mk".to_string()],
-                        ..Default::default()
-                    },
-                    Some(tree_sitter_rust::language()),
-                )),
-            ],
-        };
-
-        // matching file extension
-        assert_eq!(
-            registry.select_language("zed/lib.rs").map(|l| l.name()),
-            Some("Rust")
-        );
-        assert_eq!(
-            registry.select_language("zed/lib.mk").map(|l| l.name()),
-            Some("Make")
-        );
-
-        // matching filename
-        assert_eq!(
-            registry.select_language("zed/Makefile").map(|l| l.name()),
-            Some("Make")
-        );
-
-        // matching suffix that is not the full file extension or filename
-        assert_eq!(registry.select_language("zed/cars").map(|l| l.name()), None);
-        assert_eq!(
-            registry.select_language("zed/a.cars").map(|l| l.name()),
-            None
-        );
-        assert_eq!(registry.select_language("zed/sumk").map(|l| l.name()), None);
-    }
-}
diff --git a/crates/language/src/proto.rs b/crates/language/src/proto.rs
index c5e25fe751..3e3455c671 100644
--- a/crates/language/src/proto.rs
+++ b/crates/language/src/proto.rs
@@ -1,8 +1,6 @@
 use std::sync::Arc;
 
-use crate::Diagnostic;
-
-use super::Operation;
+use crate::{Diagnostic, Operation};
 use anyhow::{anyhow, Result};
 use clock::ReplicaId;
 use lsp::DiagnosticSeverity;
diff --git a/crates/language/src/tests.rs b/crates/language/src/tests.rs
index 4a05f108cf..800bd66290 100644
--- a/crates/language/src/tests.rs
+++ b/crates/language/src/tests.rs
@@ -1,8 +1,56 @@
 use super::*;
-use gpui::{ModelHandle, MutableAppContext};
-use std::{iter::FromIterator, rc::Rc};
+use gpui::{ModelHandle, MutableAppContext, Task};
+use std::{any::Any, cell::RefCell, ffi::OsString, iter::FromIterator, ops::Range, path::PathBuf, rc::Rc, time::{Duration, Instant, SystemTime}};
 use unindent::Unindent as _;
 
+#[test]
+fn test_select_language() {
+    let registry = LanguageRegistry {
+        languages: vec![
+            Arc::new(Language::new(
+                LanguageConfig {
+                    name: "Rust".to_string(),
+                    path_suffixes: vec!["rs".to_string()],
+                    ..Default::default()
+                },
+                Some(tree_sitter_rust::language()),
+            )),
+            Arc::new(Language::new(
+                LanguageConfig {
+                    name: "Make".to_string(),
+                    path_suffixes: vec!["Makefile".to_string(), "mk".to_string()],
+                    ..Default::default()
+                },
+                Some(tree_sitter_rust::language()),
+            )),
+        ],
+    };
+
+    // matching file extension
+    assert_eq!(
+        registry.select_language("zed/lib.rs").map(|l| l.name()),
+        Some("Rust")
+    );
+    assert_eq!(
+        registry.select_language("zed/lib.mk").map(|l| l.name()),
+        Some("Make")
+    );
+
+    // matching filename
+    assert_eq!(
+        registry.select_language("zed/Makefile").map(|l| l.name()),
+        Some("Make")
+    );
+
+    // matching suffix that is not the full file extension or filename
+    assert_eq!(registry.select_language("zed/cars").map(|l| l.name()), None);
+    assert_eq!(
+        registry.select_language("zed/a.cars").map(|l| l.name()),
+        None
+    );
+    assert_eq!(registry.select_language("zed/sumk").map(|l| l.name()), None);
+}
+
 #[gpui::test]
 fn test_edit_events(cx: &mut gpui::MutableAppContext) {
     let mut now = Instant::now();
diff --git a/crates/lsp/Cargo.toml b/crates/lsp/Cargo.toml
index 263eed76fb..76387182f3 100644
--- a/crates/lsp/Cargo.toml
+++ b/crates/lsp/Cargo.toml
@@ -3,6 +3,9 @@ name = "lsp"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/lsp.rs"
+
 [features]
 test-support = ["async-pipe"]
 
diff --git a/crates/lsp/src/lib.rs b/crates/lsp/src/lsp.rs
similarity index 100%
rename from crates/lsp/src/lib.rs
rename to crates/lsp/src/lsp.rs
diff --git a/crates/project/Cargo.toml b/crates/project/Cargo.toml
index 98b73508f6..fce637c8e7 100644
--- a/crates/project/Cargo.toml
+++ b/crates/project/Cargo.toml
@@ -3,6 +3,9 @@ name = "project"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/project.rs"
+
 [features]
 test-support = ["language/test-support", "text/test-support"]
 
diff --git a/crates/project/src/lib.rs b/crates/project/src/project.rs
similarity index 100%
rename from crates/project/src/lib.rs
rename to crates/project/src/project.rs
diff --git a/crates/project_panel/Cargo.toml b/crates/project_panel/Cargo.toml
index 180ea078e1..eb9d76eaa9 100644
--- a/crates/project_panel/Cargo.toml
+++ b/crates/project_panel/Cargo.toml
@@ -3,6 +3,9 @@ name = "project_panel"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/project_panel.rs"
+
 [dependencies]
 gpui = { path = "../gpui" }
 project = { path = "../project" }
diff --git a/crates/project_panel/src/lib.rs b/crates/project_panel/src/project_panel.rs
similarity index 100%
rename from crates/project_panel/src/lib.rs
rename to crates/project_panel/src/project_panel.rs
diff --git a/crates/rpc/Cargo.toml b/crates/rpc/Cargo.toml
index f8c1e7d39c..55f8a50d7f 100644
--- a/crates/rpc/Cargo.toml
+++ b/crates/rpc/Cargo.toml
@@ -4,6 +4,9 @@ edition = "2018"
 name = "rpc"
 version = "0.1.0"
 
+[lib]
+path = "src/rpc.rs"
+
 [features]
 test-support = []
 
diff --git a/crates/rpc/src/lib.rs b/crates/rpc/src/rpc.rs
similarity index 100%
rename from crates/rpc/src/lib.rs
rename to crates/rpc/src/rpc.rs
diff --git a/crates/sum_tree/Cargo.toml b/crates/sum_tree/Cargo.toml
index 6a9893502e..20d6526204 100644
--- a/crates/sum_tree/Cargo.toml
+++ b/crates/sum_tree/Cargo.toml
@@ -3,6 +3,9 @@ name = "sum_tree"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/sum_tree.rs"
+
 [dependencies]
 arrayvec = "0.7.1"
 
diff --git a/crates/sum_tree/src/lib.rs b/crates/sum_tree/src/sum_tree.rs
similarity index 100%
rename from crates/sum_tree/src/lib.rs
rename to crates/sum_tree/src/sum_tree.rs
diff --git a/crates/theme/Cargo.toml b/crates/theme/Cargo.toml
index a02683ec07..1e5d38f44d 100644
--- a/crates/theme/Cargo.toml
+++ b/crates/theme/Cargo.toml
@@ -3,6 +3,9 @@ name = "theme"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/theme.rs"
+
 [dependencies]
 gpui = { path = "../gpui" }
 anyhow = "1.0.38"
diff --git a/crates/theme/src/lib.rs b/crates/theme/src/theme.rs
similarity index 100%
rename from crates/theme/src/lib.rs
rename to crates/theme/src/theme.rs
diff --git a/crates/theme_selector/Cargo.toml b/crates/theme_selector/Cargo.toml
index e4ef6d768d..e1b253595f 100644
--- a/crates/theme_selector/Cargo.toml
+++ b/crates/theme_selector/Cargo.toml
@@ -3,6 +3,9 @@ name = "theme_selector"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/theme_selector.rs"
+
 [dependencies]
 editor = { path = "../editor" }
 fuzzy = { path = "../fuzzy" }
diff --git a/crates/theme_selector/src/lib.rs b/crates/theme_selector/src/theme_selector.rs
similarity index 100%
rename from crates/theme_selector/src/lib.rs
rename to crates/theme_selector/src/theme_selector.rs
diff --git a/crates/workspace/Cargo.toml b/crates/workspace/Cargo.toml
index b20ab232f9..29e25148e5 100644
--- a/crates/workspace/Cargo.toml
+++ b/crates/workspace/Cargo.toml
@@ -3,6 +3,9 @@ name = "workspace"
 version = "0.1.0"
 edition = "2018"
 
+[lib]
+path = "src/workspace.rs"
+
 [features]
 test-support = [
     "client/test-support",
diff --git a/crates/workspace/src/lib.rs b/crates/workspace/src/workspace.rs
similarity index 100%
rename from crates/workspace/src/lib.rs
rename to crates/workspace/src/workspace.rs
diff --git a/crates/zed/Cargo.toml b/crates/zed/Cargo.toml
index 485011d5e4..9657691fc9 100644
--- a/crates/zed/Cargo.toml
+++ b/crates/zed/Cargo.toml
@@ -7,7 +7,7 @@ version = "0.9.0"
 
 [lib]
 name = "zed"
-path = "src/lib.rs"
+path = "src/zed.rs"
 
 [[bin]]
 name = "Zed"
diff --git a/crates/zed/src/lib.rs b/crates/zed/src/zed.rs
similarity index 100%
rename from crates/zed/src/lib.rs
rename to crates/zed/src/zed.rs