feat(types + tests): updated types and tests for @lune/fs

tests/fs/files.luau

@@ -9,22 +9,35 @@ local utils = require("./utils")
 fs.writeDir(TEMP_DIR_PATH)
 fs.writeDir(TEMP_ROOT_PATH)
 
--- Write both of our files
+-- Write both of our files with string and buffer contents
 
 fs.writeFile(TEMP_ROOT_PATH .. "/test_binary", utils.binaryBlob)
 fs.writeFile(TEMP_ROOT_PATH .. "/test_json.json", utils.jsonBlob)
 
+fs.writeFile(TEMP_ROOT_PATH .. "/test_binary_buf", buffer.fromstring(utils.binaryBlob))
+fs.writeFile(TEMP_ROOT_PATH .. "/test_json_buf.json", buffer.fromstring(utils.jsonBlob))
+
 -- Make sure reading the file we just
 -- wrote gets us back the original strings
 
 assert(
-	fs.readFile(TEMP_ROOT_PATH .. "/test_binary") == utils.binaryBlob,
+	buffer.tostring(fs.readFile(TEMP_ROOT_PATH .. "/test_binary")) == utils.binaryBlob,
-	"Binary file round-trip resulted in different strings"
+	"(String) Binary file round-trip resulted in different strings"
 )
 
 assert(
-	fs.readFile(TEMP_ROOT_PATH .. "/test_json.json") == utils.jsonBlob,
+	buffer.tostring(fs.readFile(TEMP_ROOT_PATH .. "/test_json.json")) == utils.jsonBlob,
-	"JSON file round-trip resulted in different strings"
+	"(String) JSON file round-trip resulted in different strings"
+)
+
+assert(
+	buffer.tostring(fs.readFile(TEMP_ROOT_PATH .. "/test_binary_buf")) == utils.binaryBlob,
+	"(Buffer) Binary file round-trip resulted in different strings"
+)
+
+assert(
+	buffer.tostring(fs.readFile(TEMP_ROOT_PATH .. "/test_json_buf.json")) == utils.jsonBlob,
+	"(Buffer) JSON file round-trip resulted in different strings"
 )
 
 -- Make sure file checks succeed but dir checks fail

types/fs.luau

@@ -107,7 +107,7 @@ local fs = {}
 	@param path The path to the file to read
 	@return The contents of the file
 ]=]
-function fs.readFile(path: string): string
+function fs.readFile(path: string): buffer
 	return nil :: any
 end
 
@@ -144,7 +144,7 @@ end
 	@param path The path of the file
 	@param contents The contents of the file
 ]=]
-function fs.writeFile(path: string, contents: string) end
+function fs.writeFile(path: string, contents: buffer | string) end
 
 --[=[
 	@within FS