diff --git a/dash-frontend/src/lib.rs b/dash-frontend/src/lib.rs
index 916ed0cf..ce508442 100644
--- a/dash-frontend/src/lib.rs
+++ b/dash-frontend/src/lib.rs
@@ -1,6 +1,7 @@
 mod assets;
 pub mod frontend;
 mod tab;
+mod test;
 mod util;
 mod various;
 mod views;
diff --git a/dash-frontend/src/tab/settings/tab_features.rs b/dash-frontend/src/tab/settings/tab_features.rs
index 100e941f..cc2c9161 100644
--- a/dash-frontend/src/tab/settings/tab_features.rs
+++ b/dash-frontend/src/tab/settings/tab_features.rs
@@ -58,13 +58,14 @@ impl SettingsTab for State {
 			match task {
 				Task::WhisperDownloadClosed => {
 					if let Some(model) = self.pending_download.take()
-						&& !whisper_model_path(model.file_name).exists() {
-							// download failed, set to selection to none
-							par.general_config.whisper_model = "".into();
-							par.config_change_kind.replace(ConfigChangeKind::Other);
-							// reload the tab
-							self.parent_tasks.push(ParentTask::SetTab(TabNameEnum::Features));
-						}
+						&& !whisper_model_path(model.file_name).exists()
+					{
+						// download failed, set to selection to none
+						par.general_config.whisper_model = "".into();
+						par.config_change_kind.replace(ConfigChangeKind::Other);
+						// reload the tab
+						self.parent_tasks.push(ParentTask::SetTab(TabNameEnum::Features));
+					}
 				}
 				Task::WhisperRemoveUnused => {
 					let _ = whisper_delete_all_models().log_err("could not remove whisper models");
diff --git a/dash-frontend/src/test.rs b/dash-frontend/src/test.rs
new file mode 100644
index 00000000..0d781cfd
--- /dev/null
+++ b/dash-frontend/src/test.rs
@@ -0,0 +1,104 @@
+#[cfg(test)]
+mod tests {
+	use crate::assets::Asset;
+
+	#[test]
+	fn lang_json_files_are_valid() {
+		for file in Asset::iter() {
+			if file.ends_with(".json") {
+				let data = Asset::get(&file).unwrap_or_else(|| panic!("embedded file {file} not found"));
+				let text =
+					String::from_utf8(data.data.to_vec()).unwrap_or_else(|e| panic!("file {file} is not valid UTF-8: {e}"));
+				serde_json::from_str::<serde_json::Value>(&text)
+					.unwrap_or_else(|e| panic!("file {file} is not valid JSON: {e}"));
+			}
+		}
+	}
+
+	fn parse_csv_keys(data: &[u8]) -> Vec<String> {
+		let text = std::str::from_utf8(data).expect("en.csv is not valid UTF-8");
+		let mut keys = Vec::new();
+		let mut chars = text.chars().peekable();
+		while chars.peek().is_some() {
+			let key = read_csv_field(&mut chars);
+			// skip comma separator
+			if chars.peek() == Some(&',') {
+				chars.next();
+			}
+			// skip value field
+			read_csv_field(&mut chars);
+			// skip comma separator
+			if chars.peek() == Some(&',') {
+				chars.next();
+			}
+			// skip description field (may contain newlines via quotes)
+			read_csv_field(&mut chars);
+			// skip newline
+			if chars.peek() == Some(&'\n') {
+				chars.next();
+			}
+			keys.push(key);
+		}
+		keys
+	}
+
+	fn read_csv_field(chars: &mut std::iter::Peekable<std::str::Chars>) -> String {
+		let mut field = String::new();
+		if chars.peek() == Some(&'"') {
+			// quoted field
+			chars.next(); // consume opening quote
+			loop {
+				match chars.next() {
+					Some('"') => {
+						if chars.peek() == Some(&'"') {
+							field.push('"'); // escaped quote
+							chars.next();
+						} else {
+							break; // closing quote
+						}
+					}
+					Some(c) => field.push(c),
+					None => break,
+				}
+			}
+		} else {
+			// unquoted field
+			for c in chars.by_ref() {
+				if c == ',' || c == '\n' {
+					break;
+				}
+				field.push(c);
+			}
+		}
+		field
+	}
+
+	fn get_nested<'a>(value: &'a serde_json::Value, key: &str) -> Option<&'a serde_json::Value> {
+		let mut current = value;
+		for segment in key.split('.') {
+			current = current.get(segment)?;
+		}
+		Some(current)
+	}
+
+	#[test]
+	fn lang_json_files_contain_all_keys() {
+		let en_data = Asset::get("lang/en.csv").expect("en.csv not found");
+		let expected_keys = parse_csv_keys(&en_data.data);
+
+		for file in Asset::iter() {
+			if !file.ends_with(".json") {
+				continue;
+			}
+			let data = Asset::get(&file).unwrap_or_else(|| panic!("embedded file {file} not found"));
+			let text =
+				String::from_utf8(data.data.to_vec()).unwrap_or_else(|e| panic!("file {file} is not valid UTF-8: {e}"));
+			let json: serde_json::Value =
+				serde_json::from_str(&text).unwrap_or_else(|e| panic!("file {file} is not valid JSON: {e}"));
+
+			for key in &expected_keys {
+				assert!(get_nested(&json, key).is_some(), "missing key {key} in {file}");
+			}
+		}
+	}
+}
diff --git a/wayvr/src/main.rs b/wayvr/src/main.rs
index 3e3e356a..d85a0ddc 100644
--- a/wayvr/src/main.rs
+++ b/wayvr/src/main.rs
@@ -28,6 +28,7 @@ mod overlays;
 mod shaders;
 mod state;
 mod subsystem;
+mod test;
 mod windowing;
 
 use std::{
diff --git a/wayvr/src/test.rs b/wayvr/src/test.rs
new file mode 100644
index 00000000..9e7b6f7a
--- /dev/null
+++ b/wayvr/src/test.rs
@@ -0,0 +1,109 @@
+#[cfg(test)]
+mod tests {
+    use crate::gui::asset::GuiAsset;
+
+    #[test]
+    fn lang_json_files_are_valid() {
+        for file in GuiAsset::iter() {
+            if file.ends_with(".json") {
+                let data = GuiAsset::get(&file)
+                    .unwrap_or_else(|| panic!("embedded file {file} not found"));
+                let text = String::from_utf8(data.data.to_vec())
+                    .unwrap_or_else(|e| panic!("file {file} is not valid UTF-8: {e}"));
+                serde_json::from_str::<serde_json::Value>(&text)
+                    .unwrap_or_else(|e| panic!("file {file} is not valid JSON: {e}"));
+            }
+        }
+    }
+
+    fn parse_csv_keys(data: &[u8]) -> Vec<String> {
+        let text = std::str::from_utf8(data).expect("en.csv is not valid UTF-8");
+        let mut keys = Vec::new();
+        let mut chars = text.chars().peekable();
+        while let Some(_) = chars.peek() {
+            let key = read_csv_field(&mut chars);
+            // skip comma separator
+            if chars.peek() == Some(&',') {
+                chars.next();
+            }
+            // skip value field
+            read_csv_field(&mut chars);
+            // skip comma separator
+            if chars.peek() == Some(&',') {
+                chars.next();
+            }
+            // skip description field (may contain newlines via quotes)
+            read_csv_field(&mut chars);
+            // skip newline
+            if chars.peek() == Some(&'\n') {
+                chars.next();
+            }
+            keys.push(key);
+        }
+        keys
+    }
+
+    fn read_csv_field(chars: &mut std::iter::Peekable<std::str::Chars>) -> String {
+        let mut field = String::new();
+        if chars.peek() == Some(&'"') {
+            // quoted field
+            chars.next(); // consume opening quote
+            loop {
+                match chars.next() {
+                    Some('"') => {
+                        if chars.peek() == Some(&'"') {
+                            field.push('"'); // escaped quote
+                            chars.next();
+                        } else {
+                            break; // closing quote
+                        }
+                    }
+                    Some(c) => field.push(c),
+                    None => break,
+                }
+            }
+        } else {
+            // unquoted field
+            for c in chars.by_ref() {
+                if c == ',' || c == '\n' {
+                    break;
+                }
+                field.push(c);
+            }
+        }
+        field
+    }
+
+    fn get_nested<'a>(value: &'a serde_json::Value, key: &str) -> Option<&'a serde_json::Value> {
+        let mut current = value;
+        for segment in key.split('.') {
+            current = current.get(segment)?;
+        }
+        Some(current)
+    }
+
+    #[test]
+    fn lang_json_files_contain_all_keys() {
+        let en_data = GuiAsset::get("lang/en.csv").expect("en.csv not found");
+        let expected_keys = parse_csv_keys(&en_data.data);
+
+        for file in GuiAsset::iter() {
+            if !file.ends_with(".json") {
+                continue;
+            }
+            let data =
+                GuiAsset::get(&file).unwrap_or_else(|| panic!("embedded file {file} not found"));
+            let text = String::from_utf8(data.data.to_vec())
+                .unwrap_or_else(|e| panic!("file {file} is not valid UTF-8: {e}"));
+            let json: serde_json::Value = serde_json::from_str(&text)
+                .unwrap_or_else(|e| panic!("file {file} is not valid JSON: {e}"));
+
+            for key in &expected_keys {
+                assert!(
+                    get_nested(&json, key).is_some(),
+                    "missing key {key} in {file}"
+                );
+            }
+        }
+    }
+}