Hoist the FileHandle check and add more tests

Author: Assumeru

apps/openmw/mwlua/vfsbindings.cpp

@@ -190,9 +190,9 @@ namespace MWLua
                 return seek(lua, self, std::ios_base::cur, off);
             });
         handle["lines"] = [](sol::this_state lua, sol::object self) {
+            if (!self.is<FileHandle*>())
+                throw std::runtime_error("self should be a file handle");
             return sol::as_function([lua, self]() -> sol::object {
-                if (!self.is<FileHandle*>())
-                    return sol::nil;
                 FileHandle* handle = self.as<FileHandle*>();
                 validateFile(*handle);
                 return readLineFromFile(lua, *handle);

scripts/data/integration_tests/test_lua_api/test.lua

@@ -227,16 +227,18 @@ end
 
 local function testVFS()
     local file = 'test_vfs_dir/lines.txt'
+    local nosuchfile = 'test_vfs_dir/nosuchfile'
     testing.expectEqual(vfs.fileExists(file), true, 'lines.txt should exist')
-    testing.expectEqual(vfs.fileExists('test_vfs_dir/nosuchfile'), false, 'nosuchfile should not exist')
+    testing.expectEqual(vfs.fileExists(nosuchfile), false, 'nosuchfile should not exist')
 
+    local expectedLines = { '1', '2', '', '4' }
     local getLine = vfs.lines(file)
-    for _,v in pairs({ '1', '2', '', '4' }) do
+    for _,v in pairs(expectedLines) do
         testing.expectEqual(getLine(), v)
     end
     testing.expectEqual(getLine(), nil, 'All lines should have been read')
     local ok = pcall(function()
-        vfs.lines('test_vfs_dir/nosuchfile')
+        vfs.lines(nosuchfile)
     end)
     testing.expectEqual(ok, false, 'Should not be able to read lines from nonexistent file')
 
@@ -259,6 +261,14 @@ local function testVFS()
 
     testing.expectEqual(handle:close(), true, 'File should be closeable')
     testing.expectEqual(vfs.type(handle), 'closed file', 'File should be closed')
+
+    handle = vfs.open(nosuchfile)
+    testing.expectEqual(handle, nil, 'vfs.open should return nil on nonexistent files')
+
+    getLine = vfs.open(file):lines()
+    for _,v in pairs(expectedLines) do
+        testing.expectEqual(getLine(), v)
+    end
 end
 
 local function testCommitCrime()