don't show ? for unknown bin version in message about inability to determine version

Author: toy

CHANGELOG.markdown

@@ -2,6 +2,7 @@
 
 ## unreleased
 
+* Don't show `?` for unknown bin version in message about inability to determine version [@toy](https://github.com/toy)
 * Deduplicate bin resolving error messages [@toy](https://github.com/toy)
 
 ## v0.24.0 (2016-08-14)

lib/image_optim/bin_resolver/bin.rb

@@ -48,7 +48,9 @@ def to_s
 
       # Fail if version will not work properly
       def check_fail!
-        fail UnknownVersion, "didn't get version of #{self}" unless version
+        unless version
+          fail UnknownVersion, "could not get version of #{name} at #{path}"
+        end
 
         FAIL_CHECKS.each do |bin_name, matcher, message|
           next unless bin_name == name

spec/image_optim/bin_resolver_spec.rb

@@ -255,7 +255,7 @@ def raises_error(error_message)
       5.times do
         expect do
           resolver.resolve!(:pngcrush)
-        end.to raise_error Bin::UnknownVersion
+        end.to raise_error Bin::UnknownVersion, %r{pngcrush at /bin/pngcrush}
       end
     end