test require and metamethods with a simple decimal lib

test/luerl_return_SUITE.erl

@@ -16,8 +16,16 @@
 
 -include_lib("common_test/include/ct.hrl").
 
--export([all/0, groups/0]).
--export([simple_return/1, fun_return/1]).
+-export([all/0, groups/0, init_per_suite/1, end_per_suite/1]).
+-export([simple_return/1, fun_return/1, use_lib/1]).
+
+init_per_suite(Config) ->
+  DataDir = ?config(data_dir, Config),
+  os:putenv("LUA_PATH", DataDir ++ "?.lua;" ++ DataDir ++ "?/init.lua"),
+  Config.
+
+end_per_suite(Config) ->
+  Config.
 
 all() ->
   [
@@ -26,7 +34,7 @@ all() ->
 
 groups() ->
   [
-    {return, [parallel], [simple_return, fun_return]}
+    {return, [parallel], [simple_return, fun_return, use_lib]}
   ].
 
 simple_return(Config) ->
@@ -39,11 +47,17 @@ simple_return(Config) ->
 fun_return(Config) ->
   run_and_check(Config, "fun_return_multi.lua", [7, <<"str 1">>, 5.5, 11.0]).
 
+use_lib(Config) ->
+  LuaDecimal = fun(B, E) -> [{<<"b">>, B}, {<<"e">>, E}] end,
+  Expected = [LuaDecimal(B, E) || {B, E} <- [{13, 1}, {7, 1}, {3, 3}]],
+  run_and_check(Config, "decimal_test.lua", Expected).
+
 run_tests(Config, Tests) ->
   [run_and_check(Config, Script, Expected) || {Script, Expected} <- Tests].
 
 run_and_check(Config, Script, Expected) ->
   DataDir = ?config(data_dir, Config),
   ScriptFile = DataDir ++ Script,
-  {Result, _St} = luerl:dofile(ScriptFile),
-  Expected = Result.
+  {ok, Result} = luerl:evalfile(ScriptFile),
+  {true, {expected, Expected}, {result, Result}} =
+    {Result =:= Expected, {expected, Expected}, {result, Result}}.

test/luerl_return_SUITE_data/decimal.lua

@@ -0,0 +1,56 @@
+local Decimal = {}
+
+Decimal.mt = {
+    __tostring = function(d)
+        return d.b .. "e" .. d.e
+    end,
+
+    __add = function(a, b)
+        a, b = Decimal.same_e(a, b)
+
+        if a.e == b.e then
+            return Decimal.new(a.b + b.b, a.e)
+        end
+    end,
+    __sub = function(a, b)
+        return a + Decimal.new(-b.b, b.e)
+    end,
+    __mul = function(a, b)
+        return Decimal.new(a.b * b.b, a.e + b.e)
+    end,
+    __div = function(a, b)
+        -- @todo fix
+        return Decimal.new(a.b / b.b, a.e - b.e)
+    end,
+
+    __eq = function(a, b)
+        a, b = Decimal.same_e(a, b)
+        return a.b == b.b and a.e == b.e
+    end
+}
+
+Decimal.new = function(b, e)
+    local d = {
+        b = b,
+        e = e
+    }
+    setmetatable(d, Decimal.mt)
+    return d
+end
+
+Decimal.change_e = function(d, e)
+    if d.e == e then
+        return d
+    end
+    if d.e > e then
+        return Decimal.change_e(Decimal.new(10 * d.b, d.e - 1), e)
+    end
+    error("can't increment exponential")
+end
+
+Decimal.same_e = function(a, b)
+    local min_e = math.min(a.e, b.e)
+    return Decimal.change_e(a, min_e), Decimal.change_e(b, min_e)
+end
+
+return Decimal

test/luerl_return_SUITE_data/decimal_test.lua

@@ -0,0 +1,31 @@
+local d = require("decimal")
+
+a = d.new(1, 2) -- 100
+b = d.new(3, 1) -- 30
+
+print(a, "+", b, "=", a + b)
+print(a, "-", b, "=", a - b)
+print(a, "*", b, "=", a * b)
+print(a, "/", b, "=", a / b)
+
+x1 = d.new(1, 2)
+x2 = d.new(2, 2)
+x3 = d.new(2, 1)
+x4 = d.new(10, 1)
+x5 = d.new(10, 2)
+print(a, "==", b, "=", a == b)
+print(a, "==", x1, "=", a == x1)
+print(a, "==", x2, "=", a == x2)
+print(a, "==", x3, "=", a == x3)
+print(a, "==", x4, "=", a == x4)
+print(a, "==", x5, "=", a == x5)
+
+assert(a + b == d.new(130, 0))
+assert(a + b == d.new(13, 1))
+assert(a - b == d.new(70, 0))
+assert(a - b == d.new(7, 1))
+assert(a * b == d.new(3000, 0))
+assert(a * b == d.new(3, 3))
+--assert(a / b == d.new(33333333333333, -15))
+
+return a + b, a - b, a * b