lumiera_documentation/tests/lib/format-helper-test.cpp
Ichthyostega a835a796b2 Library: investigate further ramifications and clean-up Itertools
The detailed analysis of corner cases indicated a lot of hidden dangers
when stretching the `IterExplorer` design beyond its limits.

By deliberate choice, this design was kept open so that advanced cohesive
implementation structures can be built. It is even possible ''and tolerated''
to rely on ''references'' to some degree -- assuming however that the
referred memory location remains stable.

As it turned out, these basic assumptions can be broken by a combination
of read-ahead processing (as is necessary for grouping and filtering),
together with adaptor objects embedded as value, especially when
the resulting pipeline object is then moved or copied during evaluation.

While my general attitude towards such extremely clever implementation
constructs is "don't shoot yourself into your foot unless you need to" --
it seems prudent to clean-up some crappy code from the first attempts
towards an iterator pipeline -- notably some of the »Itertools«.
2026-04-01 01:49:36 +02:00

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/*
FormatHelper(Test) - validate formatting and diagnostics helpers
Copyright (C)
2009, Hermann Vosseler <Ichthyostega@web.de>
  **Lumiera** is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License as published by the
  Free Software Foundation; either version 2 of the License, or (at your
  option) any later version. See the file COPYING for further details.
* *****************************************************************/
/** @file format-helper-test.cpp
** unit test \ref FormatHelper_test
*/
#include "test/run.hpp"
#include "lib/format-util.hpp"
#include "lib/format-string.hpp"
#include "lib/iter-adapter-stl.hpp"
#include "test/test-helper.hpp"
#include "lib/error.hpp"
#include <vector>
#include <string>
using lumiera::error::Fatal;
using lib::iter_stl::snapshot;
using lib::iter_stl::eachElm;
using lib::transformIter;
using lib::eachNum;
using util::_Fmt;
using std::vector;
using std::string;
using std::to_string;
namespace util {
namespace test {
namespace { // test fixture...
class Reticent
{ };
class UnReticent
: public Reticent
{
public:
operator string() const { return "hey Joe!"; }
};
class Bomb
{
public:
operator string() const { throw Fatal{"mistake"}; }
};
class AutoCounter
{
static uint cnt;
uint id_;
double d_;
public:
AutoCounter(double d)
: id_(++cnt)
, d_(d*2)
{ }
operator string() const
{
return _Fmt("Nr.%02d(%3.1f)") % id_ % d_;
}
};
uint AutoCounter::cnt = 0;
}
/***************************************************************************//**
* @test verifies the proper working of some string-formatting helper functions.
* - util::toString() provides a failsafe to-String conversion, preferring
* an built-in conversion, falling back to just a type string.
* - util::join() combines elements from arbitrary containers or iterators
* into a string, relying on aforementioned generic string conversion
* @see format-util.hpp
*/
class FormatHelper_test
: public Test
{
void
run (Arg)
{
check2String();
checkStringify();
checkStringJoin();
checkPrefixSuffix();
}
/** @test verify a failsafe to-string conversion. */
void
check2String ()
{
Reticent closeLipped;
UnReticent chatterer;
CHECK (toString (closeLipped) == "«Reticent»"_expect);
CHECK (toString (chatterer) == "hey Joe!"_expect);
CHECK (toString (&chatterer) == "↗hey Joe!"_expect); // pointer indicated
CHECK (toString (Bomb{}) == "↯"_expect); // runtime exception, caught
CHECK (toString (true) == "true"_expect); // special handling for bool
CHECK (toString (2+2 == 5) == "false"_expect);
CHECK (toString (12.34e55) == "1.234e+56"_expect);
CHECK (toString (short(12))
+toString (345L)
+toString ("67")
+toString ('8') == "12345678"_expect); // these go through lexical_cast<string>
}
/** @test inline to-string converter function
* - can be used as transforming iterator
* - alternatively accept arbitrary arguments
*/
void
checkStringify()
{
// use as transformer within an (iterator) pipeline
auto ss = stringify (eachNum (1.11, 10.2));
CHECK (ss);
CHECK ("1.11" == *ss);
++ss;
CHECK ("2.11" == *ss);
string res{".."};
for (auto s : ss)
res += s;
CHECK (res == "..2.113.114.115.116.117.118.119.1110.11"_expect);
using VecS = vector<string>;
// another variant: collect arbitrary heterogeneous arguments
VecS vals = stringify (short(12), 345L, "67", '8');
CHECK (vals == VecS({"12", "345", "67", "8"}));
// stringify can both consume (RValue-Ref) or take a copy from its source
auto nn = snapshot (eachNum (5, 10));
CHECK (5 == *nn);
++nn;
CHECK (6 == *nn);
auto sn = stringify (nn);
CHECK ("6" == *sn);
++sn;
CHECK ("7" == *sn);
CHECK (6 == *nn);
++++nn;
CHECK (8 == *nn);
CHECK ("7" == *sn);
sn = stringify (std::move(nn));
CHECK ("8" == *sn);
CHECK (isnil (nn)); // was consumed by moving it into sn
++sn;
CHECK ("9" == *sn);
++sn;
CHECK (isnil (sn));
}
/** @test verify delimiter separated joining of arbitrary collections.
* - the first test uses a STL container, which means we need to wrap
* into a lib::RangeIter. Moreover, lexical_cast is used to convert
* the double numbers into strings.
* - the second test uses an inline transforming iterator to build a
* series of AutoCounter objects, which provide a custom string
* conversion function. Moreover, since the transforming iterator
* conforms to the Lumiera Forward Iterator concept, we can just
* move the rvalue into the formatting function without much ado
*/
void
checkStringJoin()
{
vector<double> dubious;
for (uint i=0; i<10; ++i)
dubious.push_back(1.1*i);
std::function<AutoCounter(double)> justCount = [](double d){ return AutoCounter(d); };
CHECK (join (dubious, "--+--")
== "0--+--"
"1.1--+--"
"2.2--+--"
"3.3--+--"
"4.4--+--"
"5.5--+--"
"6.6--+--"
"7.7--+--"
"8.8--+--"
"9.9"_expect);
CHECK (join (transformIter (eachElm(dubious), justCount))
== "Nr.01(0.0), "
"Nr.02(2.2), "
"Nr.03(4.4), "
"Nr.04(6.6), "
"Nr.05(8.8), "
"Nr.06(11.0), "
"Nr.07(13.2), "
"Nr.08(15.4), "
"Nr.09(17.6), "
"Nr.10(19.8)"_expect);
}
/** @test convenience helpers to deal with prefixes and suffixes */
void
checkPrefixSuffix()
{
string abcdef{"abcdef"};
CHECK (startsWith (abcdef, "abcdef"));
CHECK (startsWith (abcdef, "abcde"));
CHECK (startsWith (abcdef, "abcd"));
CHECK (startsWith (abcdef, "abc"));
CHECK (startsWith (abcdef, "ab"));
CHECK (startsWith (abcdef, "a"));
CHECK (startsWith (abcdef, ""));
CHECK (endsWith (abcdef, "abcdef"));
CHECK (endsWith (abcdef, "bcdef"));
CHECK (endsWith (abcdef, "cdef"));
CHECK (endsWith (abcdef, "def"));
CHECK (endsWith (abcdef, "ef"));
CHECK (endsWith (abcdef, "f"));
CHECK (endsWith (abcdef, ""));
CHECK (startsWith (string{}, ""));
CHECK (endsWith (string{}, ""));
CHECK (not startsWith (string{"abc"}, "abcd"));
CHECK (not startsWith (string{"a"}, "ä"));
CHECK (not startsWith (string{"ä"}, "a"));
CHECK (not endsWith (string{"abc"}, " abc"));
CHECK (not endsWith (string{"a"}, "ä"));
CHECK (not endsWith (string{"ä"}, "a"));
string abc{"abcdef"};
removePrefix(abc, "ab");
CHECK ("cdef" == abc);
removeSuffix(abc, "ef");
CHECK ("cd" == abc);
abc = "bcdef";
removePrefix(abc, "ab");
CHECK ("bcdef" == abc);
removeSuffix(abc, "abcdef");
CHECK ("bcdef" == abc);
removeSuffix(abc, "bcdef");
CHECK (isnil (abc));
}
};
LAUNCHER (FormatHelper_test, "unit common");
}} // namespace util::test