Add simple assertions library and tests

Author: khvzak

.gitignore

@@ -9,3 +9,6 @@ Cargo.lock
 
 # These are backup files generated by rustfmt
 **/*.rs.bk
+
+# VScode
+.vscode/

Cargo.toml

@@ -1,10 +1,21 @@
 [package]
 name = "mlua-stdlib"
 description = "Standard library bindings for mlua"
-version = "0.0.0"
-edition = "2021"
+version = "0.1.0"
+edition = "2024"
 license = "MIT"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[features]
+lua51 = ["mlua/lua51"]
+lua52 = ["mlua/lua52"]
+lua53 = ["mlua/lua53"]
+lua54 = ["mlua/lua54"]
+luau = ["mlua/luau"]
+
 [dependencies]
+mlua = { version = "0.11" }
+
+[dev-dependencies]
+mlua = { version = "0.11", features = ["macros"] }

lua/assertions.lua

@@ -0,0 +1,89 @@
+local assertions = {}
+
+function assertions.assert_eq(left, right, message)
+    if left ~= right then
+        if message ~= nil then
+            message = string.format("assertion `left == right` failed: %s", tostring(message))
+        else
+            message = "assertion `left == right` failed!"
+        end
+        error(string.format("%s\n  left: %s\n right: %s", message, tostring(left), tostring(right)))
+    end
+end
+
+function assertions.assert_ne(left, right, message)
+    if left == right then
+        if message ~= nil then
+            message = string.format("assertion `left ~= right` failed: %s", tostring(message))
+        else
+            message = "assertion `left ~= right` failed!"
+        end
+        error(string.format("%s\n  left: %s\n right: %s", message, tostring(left), tostring(right)))
+    end
+end
+
+local function next_level(level, k)
+    if type(k) == "string" then
+        return level .. '["' .. k .. '"]'
+    else
+        return level .. "[" .. tostring(k) .. "]"
+    end
+end
+
+local function deepcmp(left, right, level, visited, report_cb)
+    if type(left) ~= type(right) then
+        report_cb(left, right, level)
+        return false
+    end
+    if rawequal(left, right) then
+        return true
+    end
+    if type(left) ~= "table" then
+        report_cb(left, right, level)
+        return false
+    end
+
+    -- Prevent recursion
+    if visited[left] or visited[right] then
+        report_cb(left, right, level)
+        return false
+    end
+
+    -- Iterate over all keys in left and right, and compare their values recursively.
+    visited[left] = true
+    for k, v in next, left do
+        if not deepcmp(v, rawget(right, k), next_level(level, k), visited, report_cb) then
+            return false
+        end
+    end
+    visited[left] = nil
+
+    visited[right] = true
+    for k, v in next, right do
+        if not deepcmp(rawget(left, k), v, next_level(level, k), visited, report_cb) then
+            return false
+        end
+    end
+    visited[right] = nil
+
+    return true
+end
+
+function assertions.assert_same(left, right, message)
+    local left_v, right_v, level
+    local function report_cb(lv, rv, l)
+        left_v, right_v, level = lv, rv, l
+    end
+    if not deepcmp(left, right, "", {}, report_cb) then
+        if message ~= nil then
+            message = string.format("assertion `left ~ right` failed: %s", tostring(message))
+        else
+            message = "assertion `left ~ right` failed!"
+        end
+        error(
+            string.format("%s\n  left%s: %s\n right%s: %s", message, level, tostring(left_v), level, tostring(right_v))
+        )
+    end
+end
+
+return assertions

src/assertions.rs

@@ -0,0 +1,14 @@
+use mlua::{Lua, Result, Table};
+
+/// A loader for the `assertions` module.
+pub fn loader(lua: &Lua, name: String) -> Result<Table> {
+    lua.load(include_str!("../lua/assertions.lua"))
+        .set_name(format!("={name}"))
+        .call(())
+}
+
+/// Registers the `assertions` module in the given Lua state.
+pub fn register(lua: &Lua, name: Option<&str>) -> Result<()> {
+    let name = name.unwrap_or("@assertions");
+    lua.register_module(name, loader(lua, name.to_string())?)
+}

src/lib.rs

@@ -1,14 +1 @@
-pub fn add(left: usize, right: usize) -> usize {
-    left + right
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
-}
+pub mod assertions;

stylua.toml

@@ -0,0 +1,6 @@
+column_width = 120
+indent_type = "Spaces"
+indent_width = 4
+
+[sort_requires]
+enabled = true

tests/lib.rs

@@ -0,0 +1,33 @@
+#![cfg(test)]
+
+use std::path::Path;
+
+use mlua::{Lua, Result};
+
+fn make_lua() -> Result<Lua> {
+    let lua = Lua::new();
+
+    // Preload all modules
+    mlua_stdlib::assertions::register(&lua, None)?;
+
+    Ok(lua)
+}
+
+fn run_test(modname: &str) -> Result<()> {
+    let lua = make_lua()?;
+    lua.load(Path::new(&format!("tests/lua/{modname}_tests.lua")))
+        .exec()
+}
+
+macro_rules! include_tests {
+    ($($name:ident, )*) => { $(
+        #[test]
+        fn $name() -> Result<()> {
+            run_test(stringify!($name))
+        }
+    )*}
+}
+
+include_tests! {
+    assertions,
+}

tests/lua/assertions_tests.lua

@@ -0,0 +1,106 @@
+local assertions = require("@assertions")
+
+local assert_eq = assertions.assert_eq
+local assert_ne = assertions.assert_ne
+local assert_same = assertions.assert_same
+
+--
+-- Test assert_eq
+--
+assert_eq(1, 1)
+assert_eq(nil, nil)
+assert_eq(true, true)
+assert_eq("foo", "foo")
+
+local ok, err = pcall(assert_eq, 1, 2)
+assert(not ok)
+assert(err:match("assertion `left == right` failed!"))
+assert(err:match("  left: 1"))
+assert(err:match(" right: 2"))
+
+ok, err = pcall(assert_eq, 1, nil, "custom message")
+assert(not ok)
+assert(err:match("assertion `left == right` failed: custom message"))
+assert(err:match("  left: 1"))
+assert(err:match(" right: nil"))
+
+ok, err = pcall(assert_eq, "foo", "bar")
+assert(not ok)
+assert(err:match("  left: foo"))
+assert(err:match(" right: bar"))
+
+ok, err = pcall(assert_eq, {}, {})
+assert(not ok)
+assert(err:match("  left: table:"))
+assert(err:match(" right: table:"))
+
+--
+-- Test assert_ne
+--
+assert_ne(1, 2)
+assert_ne(nil, 1)
+assert_ne(true, false)
+assert_ne("foo", "bar")
+
+ok, err = pcall(assert_ne, 1, 1)
+assert(not ok)
+assert(err:match("assertion `left ~= right` failed!"))
+assert(err:match("  left: 1"))
+assert(err:match(" right: 1"))
+
+ok, err = pcall(assert_ne, nil, nil, "custom message")
+assert(not ok)
+assert(err:match("assertion `left ~= right` failed: custom message"))
+assert(err:match("  left: nil"))
+assert(err:match(" right: nil"))
+
+--
+-- Test assert_same
+--
+assert_same(1, 1)
+assert_same(nil, nil)
+assert_same(true, true)
+assert_same("foo", "foo")
+assert_same({ 1, 2, 3 }, { 1, 2, 3 })
+assert_same({ foo = "bar" }, { foo = "bar" })
+
+ok, err = pcall(assert_same, 1, 2)
+assert(not ok)
+assert(err:match("assertion `left ~ right` failed!"))
+assert(err:match("  left: 1"))
+assert(err:match(" right: 2"))
+
+ok, err = pcall(assert_same, 1, nil, "custom message")
+assert(not ok)
+assert(err:match("assertion `left ~ right` failed: custom message"))
+assert(err:match("  left: 1"))
+assert(err:match(" right: nil"))
+
+ok, err = pcall(assert_same, "foo", "bar")
+assert(not ok)
+assert(err:match("  left: foo"))
+assert(err:match(" right: bar"))
+
+ok, err = pcall(assert_same, { 1, 2, 3 }, { 1, 2, 4 })
+assert(not ok)
+assert(err:match("  left%[3%]: 3"))
+assert(err:match(" right%[3%]: 4"))
+
+ok, err = pcall(assert_same, { foo = "bar" }, { foo = "baz" })
+assert(not ok)
+assert(err:match('  left%["foo"%]: bar'))
+assert(err:match(' right%["foo"%]: baz'))
+
+-- Deep nested tables
+ok, err = pcall(assert_same, { foo = { bar = { baz = 1 } } }, { foo = { bar = { baz = function() end } } })
+assert(not ok)
+assert(err:match('  left%["foo"%]%["bar"%]%["baz"%]: 1'))
+assert(err:match(' right%["foo"%]%["bar"%]%["baz"%]: function:'))
+
+-- Recursion
+local t = {}
+t[1] = t
+ok, err = pcall(assert_same, t, { {} })
+assert(not ok)
+assert(err:match("  left%[1%]: table:"))
+assert(err:match(" right%[1%]: table:"))