Fix inclusion matcher w/ date & datetime attrs

Why:

* The inclusion matcher (when used with the `in_array` qualifier) makes
  the assertion that when the attribute is set to a value that is
  outside the given array, the record in question is invalid. The issue
  is that when used with a date or datetime attribute, the arbitrary
  value the matcher chose was a string. This was getting typecast and so
  the matcher was throwing a CouldNotSetAttributeError.

To satisfy the above:

* If the column is a date, use a Date for the arbitrary value
* If the column is a datetime, use a DateTime for the arbitrary value
* If the column is a time, use a Time for the arbitrary value

NEWS.md

@@ -1,3 +1,10 @@
+# HEAD
+
+### Bug fixes
+
+* Fix `validate_inclusion_of` + `in_array` when used against a date or datetime
+  attribute so that it does not raise a CouldNotSetAttributeError.
+
 # 3.0.0
 
 ### Backward-incompatible changes

lib/shoulda/matchers/active_model/validate_inclusion_of_matcher.rb

@@ -263,9 +263,12 @@ def validate_inclusion_of(attr)
 
       # @private
       class ValidateInclusionOfMatcher < ValidationMatcher
-        ARBITRARY_OUTSIDE_STRING = 'shouldamatchersteststring'
+        ARBITRARY_OUTSIDE_STRING = 'shoulda-matchers test string'
         ARBITRARY_OUTSIDE_FIXNUM = 123456789
         ARBITRARY_OUTSIDE_DECIMAL = BigDecimal.new('0.123456789')
+        ARBITRARY_OUTSIDE_DATE = Date.jd(9999999)
+        ARBITRARY_OUTSIDE_DATETIME = DateTime.jd(9999999)
+        ARBITRARY_OUTSIDE_TIME = Time.at(9999999999)
         BOOLEAN_ALLOWS_BOOLEAN_MESSAGE = <<EOT
 You are using `validate_inclusion_of` to assert that a boolean column allows
 boolean values and disallows non-boolean ones. Be aware that it is not possible
@@ -447,6 +450,12 @@ def outside_values
             [ARBITRARY_OUTSIDE_FIXNUM]
           when :decimal
             [ARBITRARY_OUTSIDE_DECIMAL]
+          when :date
+            [ARBITRARY_OUTSIDE_DATE]
+          when :datetime
+            [ARBITRARY_OUTSIDE_DATETIME]
+          when :time
+            [ARBITRARY_OUTSIDE_TIME]
           else
             [ARBITRARY_OUTSIDE_STRING]
           end
@@ -492,9 +501,9 @@ def attribute_column
 
         def column_type_to_attribute_type(type)
           case type
-            when :boolean, :decimal then type
             when :integer, :float then :fixnum
-            else :default
+            when :timestamp then :datetime
+            else type
           end
         end
 
@@ -503,7 +512,10 @@ def value_to_attribute_type(value)
             when true, false then :boolean
             when BigDecimal then :decimal
             when Fixnum then :fixnum
-            else :default
+            when Date then :date
+            when DateTime then :datetime
+            when Time then :time
+            else :unknown
           end
         end
       end

spec/unit/shoulda/matchers/active_model/validate_inclusion_of_matcher_spec.rb

@@ -75,7 +75,7 @@ def expect_to_match_on_values(builder, values, &block)
       end
     end
 
-    context "against a float attribute" do
+    context 'against a float attribute' do
       it_behaves_like 'it supports in_array',
         possible_values: [1.0, 2.0, 3.0, 4.0, 5.0],
         zero: 0.0,
@@ -97,7 +97,7 @@ def add_outside_value_to(values)
       end
     end
 
-    context "against a decimal attribute" do
+    context 'against a decimal attribute' do
       it_behaves_like 'it supports in_array',
         possible_values: [1.0, 2.0, 3.0, 4.0, 5.0].map { |number|
           BigDecimal.new(number.to_s)
@@ -121,6 +121,72 @@ def add_outside_value_to(values)
       end
     end
 
+    context 'against a date attribute' do
+      today = Date.today
+
+      it_behaves_like 'it supports in_array',
+        possible_values: (1..5).map { |n| today + n },
+        reserved_outside_value: described_class::ARBITRARY_OUTSIDE_DATE
+
+      it_behaves_like 'it supports in_range',
+        possible_values: (today .. today + 5)
+
+      define_method :build_object do |options = {}, &block|
+        build_object_with_generic_attribute(
+          options.merge(column_type: :date, value: today),
+          &block
+        )
+      end
+
+      def add_outside_value_to(values)
+        values + [values.last + 1]
+      end
+    end
+
+    context 'against a datetime attribute (using DateTime)' do
+      now = DateTime.now
+
+      it_behaves_like 'it supports in_array',
+        possible_values: (1..5).map { |n| now + n },
+        reserved_outside_value: described_class::ARBITRARY_OUTSIDE_DATETIME
+
+      it_behaves_like 'it supports in_range',
+        possible_values: (now .. now + 5)
+
+      define_method :build_object do |options = {}, &block|
+        build_object_with_generic_attribute(
+          options.merge(column_type: :datetime, value: now),
+          &block
+        )
+      end
+
+      def add_outside_value_to(values)
+        values + [values.last + 1]
+      end
+    end
+
+    context 'against a datetime attribute (using Time)' do
+      now = Time.now
+
+      it_behaves_like 'it supports in_array',
+        possible_values: (1..5).map { |n| now + n },
+        reserved_outside_value: described_class::ARBITRARY_OUTSIDE_TIME
+
+      it_behaves_like 'it supports in_range',
+        possible_values: (now .. now + 5)
+
+      define_method :build_object do |options = {}, &block|
+        build_object_with_generic_attribute(
+          options.merge(column_type: :time, value: now),
+          &block
+        )
+      end
+
+      def add_outside_value_to(values)
+        values + [values.last + 1]
+      end
+    end
+
     context 'against a string attribute' do
       it_behaves_like 'it supports in_array',
         possible_values: %w(foo bar baz),
@@ -270,7 +336,7 @@ def add_outside_value_to(values)
     end
 
     if zero
-      it 'matches when one of the given values is a 0' do
+      it 'matches when one of the given values is a zero' do
         valid_values = possible_values + [zero]
         builder = build_object_allowing(valid_values)
         expect_to_match_on_values(builder, valid_values)
@@ -527,7 +593,6 @@ def build_object(options = {}, &block)
       end
     end
 
-
     def build_object_with_generic_attribute(options = {}, &block)
       attribute_name = :attr
       column_type = options.fetch(:column_type)