Support partially loaded PowerAssert library

[kateinoigakukun]

This kind of partial loading could happen when underlying gems are
unavailable on some platforms (e.g. io/console/size on WebAssembly), and
so on.

[kou]

How about preventing partial load in power_assert instead?

e.g.:

diff --git a/lib/power_assert/inspector.rb b/lib/power_assert/inspector.rb
index 50bb646..6a4d8b6 100644
--- a/lib/power_assert/inspector.rb
+++ b/lib/power_assert/inspector.rb
@@ -1,5 +1,8 @@
 require 'power_assert/configuration'
-require 'io/console/size'
+begin
+  require 'io/console/size'
+rescue LoadError
+end
 
 module PowerAssert
   class InspectedValue
@@ -44,7 +47,8 @@ module PowerAssert
     def inspect
       if PowerAssert.configuration.colorize_message
         if PowerAssert.configuration.inspector == :pp
-          width = [IO.console_size[1] - 1 - @indent, 10].max
+          console_width = IO.respond_to?(:console_size) ? IO.console_size[1] : 80
+          width = [console_width - 1 - @indent, 10].max
           IRB::ColorPrinter.pp(@value, '', width)
         else
           IRB::Color.colorize_code(@value.to_s, ignore_error: true)

@k-tsj What do you think about this?

[kateinoigakukun]

@kou Thank you for quick response :)
It looks better to me and I've confirmed it works well also.

I'm fine with either solution ruby/power_assert#39

[k-tsj]

@kou @kateinoigakukun
It looks good. I'll merge the PR.

[kateinoigakukun]

Close in favor of the power_assert solution