Keep errors uniform

lib/baby_squeel/association.rb

@@ -2,9 +2,6 @@
 
 module BabySqueel
   class Association < Relation
-    class InvalidComparisonError < StandardError
-    end
-
     # An Active Record association reflection
     attr_reader :_reflection
 
@@ -106,18 +103,12 @@ def build_where_clause(other)
           factory = relation.send(:where_clause_factory)
           factory.build({ _reflection.name => other }, [])
         else
-          raise InvalidComparisonError, <<-EOMSG.squish
-            You can't compare association '#{_reflection.name}'
-            to #{other.class}.
-          EOMSG
+          raise AssociationComparisonError.new(_reflection.name, other)
         end
       end
     else
       def build_where_clause(_)
-        raise NotImplementedError, <<-EOMSG.squish
-          Querying association '#{_reflection.name}' with '==' and '!='
-          is only supported for ActiveRecord 5.
-        EOMSG
+        raise AssociationComparisonNotSupportedError.new(_reflection.name)
       end
     end
 

lib/baby_squeel/errors.rb

@@ -45,4 +45,20 @@ def initialize(association)
       super format(MESSAGE, association: association)
     end
   end
+
+  class AssociationComparisonError < StandardError # :nodoc:
+    def initialize(name, other)
+      super "You can't compare association '#{name}' to #{other}."
+    end
+  end
+
+  class AssociationComparisonNotSupportedError < StandardError # :nodoc:
+    MESSAGE =
+      "Querying association '%{name}' with '==' and '!=' " \
+      "is only supported for ActiveRecord >=5."
+
+    def initialize(name)
+      super format(MESSAGE, name: name)
+    end
+  end
 end

spec/baby_squeel/association_spec.rb

@@ -33,40 +33,44 @@
   end
 
   describe '#==' do
-    before do
-      if ActiveRecord::VERSION::MAJOR < 5
-        skip "This isn't supported in ActiveRecord 4"
+    if ActiveRecord::VERSION::MAJOR >= 5
+      it 'returns an wrapped Arel::Nodes::And' do
+        node = association == Author.new(id: 42)
+        expect(node._arel.left).to be_an(Arel::Nodes::Equality)
       end
-    end
-
-    it 'returns an wrapped Arel::Nodes::And' do
-      node = association == Author.new(id: 42)
-      expect(node._arel.left).to be_an(Arel::Nodes::Equality)
-    end
 
-    it 'throws for an invalid comparison' do
-      expect {
-        association == 'foo'
-      }.to raise_error(BabySqueel::Association::InvalidComparisonError)
+      it 'throws for an invalid comparison' do
+        expect {
+          association == 'foo'
+        }.to raise_error(BabySqueel::AssociationComparisonError)
+      end
+    else
+      it 'throws not supported' do
+        expect {
+          association == 'foo'
+        }.to raise_error(BabySqueel::AssociationComparisonNotSupportedError)
+      end
     end
   end
 
   describe '#!=' do
-    before do
-      if ActiveRecord::VERSION::MAJOR < 5
-        skip "This isn't supported in ActiveRecord 4"
+    if ActiveRecord::VERSION::MAJOR >= 5
+      it 'returns some wrapped arel' do
+        node = association != Author.new(id: 42)
+        expect(node._arel.left.expr).to be_an(Arel::Nodes::NotEqual)
       end
-    end
-
-    it 'returns some wrapped arel' do
-      node = association != Author.new(id: 42)
-      expect(node._arel.left.expr).to be_an(Arel::Nodes::NotEqual)
-    end
 
-    it 'throws for an invalid comparison' do
-      expect {
-        association != 'foo'
-      }.to raise_error(BabySqueel::Association::InvalidComparisonError)
+      it 'throws for an invalid comparison' do
+        expect {
+          association != 'foo'
+        }.to raise_error(BabySqueel::AssociationComparisonError)
+      end
+    else
+      it 'throws not supported' do
+        expect {
+          association != 'foo'
+        }.to raise_error(BabySqueel::AssociationComparisonNotSupportedError)
+      end
     end
   end