Allow the use of enums (#168)

spec/database_spec.cr

@@ -8,7 +8,7 @@ describe DB::Database do
 
       db.setup_connection do |cnn|
         cnn_setup += 1
-        cnn.scalar("1").should eq "1"
+        cnn.scalar("a").should eq "a"
       end
 
       cnn_setup.should eq(2)

spec/dummy_driver.cr

@@ -187,7 +187,7 @@ class DummyDriver < DB::Driver
         return (@statement.as(DummyStatement)).params[0]
       end
 
-      return n
+      n.to_i64? || n
     end
 
     def next_column_index : Int32

spec/serializable_spec.cr

@@ -81,6 +81,29 @@ class ModelWithJSON
   property c1 : String
 end
 
+struct ModelWithEnum
+  include DB::Serializable
+
+  getter c0 : Int32
+  getter c1 : MyEnum
+  # Ensure multiple enum types work together
+  getter c2 : MyOtherEnum
+
+  enum MyEnum
+    Foo  = 0
+    Bar  = 1
+    Baz  = 2
+    Quux = 3
+  end
+
+  enum MyOtherEnum
+    OMG
+    LOL
+    WTF
+    BBQ
+  end
+end
+
 macro from_dummy(query, type)
   with_dummy do |db|
     rs = db.query({{ query }})
@@ -172,6 +195,17 @@ describe "DB::Serializable" do
     expect_model("1,a", ModelWithJSON, {c0: 1, c1: "a"})
   end
 
+  it "should initialize a model with an enum property" do
+    expect_model("1,2,LOL", ModelWithEnum, {
+      c0: 1,
+      c1: ModelWithEnum::MyEnum::Baz,
+      c2: ModelWithEnum::MyOtherEnum::LOL,
+    })
+    expect_raises DB::MappingException, "Unknown enum ModelWithEnum::MyEnum value: adsf" do
+      from_dummy("1,adsf,BBQ", ModelWithEnum)
+    end
+  end
+
   it "should initialize multiple instances from a single resultset" do
     with_dummy do |db|
       db.query("1,a 2,b") do |rs|