/**
 * Authors: k.inaba
 * License: NYSL 0.9982 http://www.kmonos.net/nysl/
 *
 * Unittest helpers.
 */
module tricks.test;
import std.conv : to;
import core.exception;

/// Unittest helper that asserts an expression must throw something

void assert_throw(ExceptionType, T, string fn=__FILE__, size_t ln=__LINE__)(lazy T t, string msg="")
{
	try
		{ t(); }
	catch(ExceptionType)
		{ return; }
	catch(Throwable e)
		{ onAssertErrorMsg(fn, ln, msg.length ? msg : "exception ["~e.toString()~"]"); }
	onAssertErrorMsg(fn, ln, msg.length ? msg : "no execption");
}

/// Unittest helper that asserts an expression must not throw anything

auto assert_nothrow(T, string fn=__FILE__, size_t ln=__LINE__)(lazy T t, string msg="")
{
	try
		{ return t(); }
	catch(Throwable e)
		{ onAssertErrorMsg(fn, ln, msg.length ? msg : "exception ["~e.toString()~"]"); }
	assert(false);
}

unittest
{
	auto error = {throw new Error("hello");};
	auto nothing = (){};
	auto assertError = {assert(0);};

	assert_nothrow          ( assert_nothrow(nothing()) );
	assert_throw!AssertError( assert_nothrow(error()) );
	assert_throw!AssertError( assert_nothrow(assertError()) );

	assert_nothrow          ( assert_throw!Error(error()) );
	assert_throw!AssertError( assert_throw!Error(nothing()) );
	assert_nothrow          ( assert_throw!Error(assertError()) );
	assert_throw!AssertError( assert_throw!AssertError(error()) );
}

/// Unittest helpers asserting two values are in some relation ==, !=, <, <=, >, >=

template assertOp(string op)
{
	void assertOp(A, B, string fn=__FILE__, size_t ln=__LINE__)(A a, B b, string msg="")
	{
		try
			{ if( mixin("a"~op~"b") ) return; }
		catch(Throwable e)
			{ onAssertErrorMsg(fn, ln, msg.length ? msg : "exception ["~e.toString()~"]"); }
		onAssertErrorMsg(fn, ln, msg.length ? msg : to!string(a)~" !"~op~" "~to!string(b));
	}
}

alias assertOp!(`==`) assert_eq;
alias assertOp!(`!=`) assert_ne;
alias assertOp!(`<`)  assert_lt;
alias assertOp!(`<=`) assert_le;
alias assertOp!(`>`)  assert_gt;
alias assertOp!(`>=`) assert_ge;

unittest
{
	assert_nothrow( assert_eq(1, 1) );
	assert_nothrow( assert_ne(1, 0) );
	assert_nothrow( assert_lt(0, 1) );
	assert_nothrow( assert_le(0, 1) );
	assert_nothrow( assert_le(0, 0) );
	assert_nothrow( assert_gt(1, 0) );
	assert_nothrow( assert_ge(1, 0) );
	assert_nothrow( assert_ge(0, 0) );

	assert_throw!AssertError( assert_eq(1, 0) );
	assert_throw!AssertError( assert_ne(1, 1) );
	assert_throw!AssertError( assert_lt(1, 1) );
	assert_throw!AssertError( assert_lt(1, 0) );
	assert_throw!AssertError( assert_le(1, 0) );
	assert_throw!AssertError( assert_gt(0, 0) );
	assert_throw!AssertError( assert_gt(0, 1) );
	assert_throw!AssertError( assert_ge(0, 1) );

	class Temp { bool opEquals(int x){return x/x==x;} }
	assert_throw!AssertError( assert_eq(new Temp, 0) );
	assert_nothrow          ( assert_eq(new Temp, 1) );
	assert_throw!AssertError( assert_eq(new Temp, 2) );
}

/* [Todo] is there any way to clearnly implement "assert_compiles" and "assert_not_compile"? */
