Build warnings - comparison between doubles

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Original report (archived issue) by Ian Chen (Bitbucket: Ian Chen, GitHub: iche033).

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MsgFactory test spits out warnings on unsafe floating point comparison using the == operator which is what gtest uses inside EXPECT_EQ.

A way around this it to do a subtraction between the two and check if the abs value is less than some epsilon.

#!c++

In file included from /home/ian/depot/gazebo/gazebo/msgs/test/MsgFactory.cc:18:0:
/home/ian/depot/gazebo/test/gtest/include/gtest/gtest.h: In function ‘testing::AssertionResult testing::internal::CmpHelperEQ(const char*, const char*, const T1&, const T2&) [with T1 = double, T2 = double]’:
/home/ian/depot/gazebo/test/gtest/include/gtest/gtest.h:1353:30:   instantiated from ‘static testing::AssertionResult testing::internal::EqHelper<lhs_is_null_literal>::Compare(const char*, const char*, const T1&, const T2&) [with T1 = double, T2 = double, bool lhs_is_null_literal = false]’
/home/ian/depot/gazebo/gazebo/msgs/test/MsgFactory.cc:73:3:   instantiated from here
/home/ian/depot/gazebo/test/gtest/include/gtest/gtest.h:1316:3: warning: comparing floating point with == or != is unsafe [-Wfloat-equal]

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Original comment by Steve Peters (Bitbucket: Steven Peters, GitHub: scpeters).

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You can also use EXPECT_NEAR, ie. for x == y:

EXPECT_NEAR(x, y, 1e-6);

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Original comment by Jose Luis Rivero (Bitbucket: Jose Luis Rivero, GitHub: j-rivero).

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@scpeters is right. More information can be found in google test floating point comparison chapter.

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Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

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I'm fixing this now.

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Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

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• changed state from "new" to "resolved"

Fixed in pull request #258

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Original comment by Nate Koenig (Bitbucket: Nathan Koenig).

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• changed state from "resolved" to "closed"