Fix evolution of String --> BigDecimal

Author: johnnyshields

lib/mongoid/criteria/queryable/extensions/big_decimal.rb

@@ -33,7 +33,7 @@ def evolve(object)
                   end
                 # Always return on string for backwards compatibility with querying
                 # string-backed BigDecimal fields.
-                when BSON::Decimal128, String then obj
+                when BSON::Decimal128 then obj
                 else
                   if obj.numeric?
                     if Mongoid.map_big_decimal_to_decimal128

spec/mongoid/criteria/queryable/extensions/big_decimal_spec.rb

@@ -142,14 +142,14 @@
       end
 
       context "when provided a numeric" do
-        it "returns a string" do
+        it "returns a BSON::Decimal128" do
           expect(described_class.evolve(1)).to eq(BSON::Decimal128.new('1'))
         end
       end
 
-      context "when provided a bogus value" do
-        it "returns the value" do
-          expect(described_class.evolve(:bogus)).to eq(:bogus)
+      context "when provided a valid string" do
+        it "returns a BSON::Decimal128" do
+          expect(described_class.evolve("1")).to eq(BSON::Decimal128.new('1'))
         end
       end
 
@@ -159,9 +159,9 @@
         end
       end
 
-      context "when provided a valid string" do
-        it "returns the string" do
-          expect(described_class.evolve("1")).to eq("1")
+      context "when provided a bogus value" do
+        it "returns the value" do
+          expect(described_class.evolve(:bogus)).to eq(:bogus)
         end
       end
     end