Float output has insufficient precision to describe matcher failures

[GoogleCodeExporter]

> What steps will reproduce the problem?
Fail a DoubleEq matcher check with a large value.

> What is the expected output? What do you see instead?
The current output isn't especially helpful:

foo_test.cc:110: tried expectation #0: EXPECT_CALL(mock_obj, foo( 
DoubleEq(start), DoubleEq(end)))...
  Expected arg #0: is approximately 1260570880.4555497
           Actual: 1.26057e+09
  Expected arg #1: is approximately 1260570890.4555497
           Actual: 1.26057e+09

There isn't enough precision in the Actual display to see why the match 
failed.

The attached patch makes the Actual: line use the same output format as the 
Expected line.  This makes the output clearly show the reason for the 
matcher failure (in this case, rounding):

foo_test.cc:110: tried expectation #0: EXPECT_CALL(mock_obj, foo( 
DoubleEq(start), DoubleEq(end)))...
  Expected arg #0: is approximately 1260572265.1954534
           Actual: 1260572265
  Expected arg #1: is approximately 1260572275.1954534
           Actual: 1260572275

However, this patch also causes changes in 
test/gmock_output_test_golden.txt:

@@ -172 +172 @@
-    Function call: Bar(@0x# "Ho", 0, -0.1)
+    Function call: Bar(@0x# "Ho", 0, -0.10000000000000001)
@@ -180 +180 @@
-           Actual: -0.1
+           Actual: -0.10000000000000001

This does not seem ideal.  What is the best option here?

> What version of the product are you using? On what operating system?
SVN on GNU

Original issue reported on code.google.com by swor...@google.com on 14 Dec 2009 at 6:25

Attachments:

• gmock-print-more-float.patch

[GoogleCodeExporter]

Original comment by w...@google.com on 17 Dec 2009 at 5:43

• Changed state: Accepted
• Added labels: OpSys-All, Type-Enhancement, Usability
• Removed labels: Type-Defect

[GoogleCodeExporter]

We should fix gtest's issue 246
(http://code.google.com/p/googletest/issues/detail?id=246), then this will be 
fixed too.

Original comment by w...@google.com on 5 Jan 2010 at 4:33

[GoogleCodeExporter]

There is probably more to it than fixing gtest issue 246, as gmock may not be 
using
Message to print values here.  I have to read the code and add tests to be sure.

Original comment by w...@google.com on 6 Jan 2010 at 5:16