Convert bools to strings for output

src/spectator/matchers/predicate_matcher.cr

@@ -20,14 +20,14 @@ module Spectator::Matchers
       if match?(snapshot)
         SuccessfulMatchData.new
       else
-        FailedMatchData.new("#{actual.label} is not #{expected.label}", **snapshot)
+        FailedMatchData.new("#{actual.label} is not #{expected.label}", **values(snapshot))
       end
     end
 
     def negated_match(actual)
       snapshot = snapshot_values(actual.value)
       if match?(snapshot)
-        FailedMatchData.new("#{actual.label} is #{expected.label}", **snapshot)
+        FailedMatchData.new("#{actual.label} is #{expected.label}", **values(snapshot))
       else
         SuccessfulMatchData.new
       end
@@ -53,6 +53,16 @@ module Spectator::Matchers
       {% end %}
     end
 
+    private def values(snapshot)
+      {% begin %}
+      {
+        {% for attribute in ExpectedType.keys %}
+        {{attribute}}: snapshot[{{attribute.symbolize}}].inspect,
+        {% end %}
+      }
+      {% end %}
+    end
+
     private def match?(snapshot)
       # Test each predicate and immediately return false if one is false.
       {% for attribute in ExpectedType.keys %}