Ichthyostega
dcbde6d163
I changed the rendering of unsigned types in diagnostic output to use the short notation, e.g. `uint` instead of `unsigned int`. This dramatically improves the legibility of verification strings. Moreover, I took the opportunigy to look through the existing page with codeing style guides to explicitly write down some conventions formed over years of usage. I did not just »make up« those light heartedly, rather these conventions are the result of a craftsman's ''attentive observation and self-reflection.''
145 lines
5 KiB
C++
145 lines
5 KiB
C++
/*
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Result(Test) - verify the either-result-or-failure intermediary wrapper
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Copyright (C)
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2023, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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* *****************************************************************/
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/** @file result-test.cpp
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** unit test \ref Result_test
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*/
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#include "lib/test/run.hpp"
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#include "lib/test/test-helper.hpp"
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#include "lib/result.hpp"
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#include "lib/util.hpp"
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#include <cstdlib>
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namespace lib {
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namespace test{
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using util::isSameObject;
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using std::rand;
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namespace error = lumiera::error;
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using error::LUMIERA_ERROR_FATAL;
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using error::LUMIERA_ERROR_STATE;
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namespace {
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const Literal THE_END = "all dead and hero got the girl";
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#define Type(_EXPR_) lib::test::showType<decltype(_EXPR_)>()
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}
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/***********************************************************************************//**
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* @test Verify an intermediary »Either« type, to embody either a successful result,
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* or document a failure with encountered exception.
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* - when given a value, the Result captures it and is in »left« state
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* - various value types can be picked up by perfect forwarding
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* - when given an exception, the result is in »right« state
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* - option-style `or-else` usage
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* - can invoke arbitrary _callable_ and capture result or exception caught
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* - invocation also works with void functors, and likewise captures failure
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* @see result.hpp
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* @see lib::ThreadJoinable usage example
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*/
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class Result_test
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: public Test
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{
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void
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run (Arg)
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{
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auto happy = Result{THE_END};
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CHECK (happy == THE_END);
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CHECK (happy.isValid());
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CHECK (bool(happy));
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happy.maybeThrow(); // still alive...
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CHECK (Type(happy) == "Result<Literal const&>"_expect);
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// Note type deduction: RValue moved into the Result...
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auto sequel = Result{Literal{THE_END}};
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CHECK (sequel.isValid());
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CHECK (Type(sequel) == "Result<Literal>"_expect);
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CHECK ( isSameObject (happy.get<Literal const&>(), THE_END));
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CHECK (not isSameObject (sequel.get<Literal const&>(), THE_END));
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// »Either Right« case : mark as failure
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Result<double> facepalm{error::Fatal("zOMG")};
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CHECK (not facepalm.isValid());
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VERIFY_ERROR (FATAL, (double)facepalm );
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VERIFY_ERROR (FATAL, facepalm.get<double&>());
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VERIFY_ERROR (FATAL, facepalm.maybeThrow() );
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CHECK (42.0 == facepalm.or_else([]{ return 42; }));
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CHECK (42.0 == facepalm.value_or(210/5));
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// a generic functor (template) to invoke
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auto evil = [](auto it)
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{
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if (it % 2)
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throw error::State{"conspiracy"};
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else
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return it;
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};
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// Invoke failsafe and capture result....
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auto seed = Result{evil, '*'}; // this invocation is successful
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CHECK (Type(seed) == "Result<char>"_expect); // generic λ instantiated with <char>
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CHECK (42 == seed); // int('*') == 42
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auto breed = Result{evil, 55ll}; // an odd number...
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VERIFY_ERROR (STATE, breed.maybeThrow() );
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CHECK (Type(breed) == "Result<llong>"_expect);
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auto dead = Result{[]{ throw 55; }};
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auto deed = Result{[]{ /* :-) */ }};
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CHECK (Type(dead) == "Result<void>"_expect);
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CHECK (Type(deed) == "Result<void>"_expect);
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CHECK (not dead.isValid());
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CHECK ( deed.isValid());
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try { dead.maybeThrow(); } // can handle really *anything* thrown
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catch(int oo)
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{ CHECK (oo == 55); }
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// can also invoke member function....
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auto deaf = Result{&Literal::empty, &THE_END}; // Note: instance "this"-ptr as first argument
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CHECK (deaf.isValid()); // no exception was thrown => state isValid()
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CHECK (deaf == false); // yet invocation of THE_END.empty() yields false
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CHECK (not deaf); // Warning: in this case, the conversion to payload type shadows
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CHECK (Type(deaf) == "Result<bool>"_expect);
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}
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};
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/** Register this test class... */
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LAUNCHER (Result_test, "unit common");
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}} // namespace lib::test
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