tests, favor public API over inspecting columns where possible.

This is a follow up to 07786c5e75
and cd2596f55e

activerecord/test/cases/defaults_test.rb

@@ -20,9 +20,9 @@ class DefaultTest < ActiveRecord::TestCase
 
   if current_adapter?(:PostgreSQLAdapter)
     def test_multiline_default_text
+      record = Default.new
       # older postgres versions represent the default with escapes ("\\012" for a newline)
-      assert( "--- []\n\n" == Default.columns_hash['multiline_default'].default ||
-               "--- []\\012\\012" == Default.columns_hash['multiline_default'].default)
+      assert("--- []\n\n" == record.multiline_default || "--- []\\012\\012" == record.multiline_default)
     end
   end
 end
@@ -51,7 +51,7 @@ class DefaultNumbersTest < ActiveRecord::TestCase
 
   def test_default_negative_integer
     record = DefaultNumber.new
-    assert_equal -5, record.negative_integer
+    assert_equal (-5), record.negative_integer
     assert_equal "-5", record.negative_integer_before_type_cast
   end
 
@@ -122,19 +122,21 @@ if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
     def test_mysql_text_not_null_defaults_non_strict
       using_strict(false) do
         with_text_blob_not_null_table do |klass|
-          assert_equal '', klass.columns_hash['non_null_blob'].default
-          assert_equal '', klass.columns_hash['non_null_text'].default
+          record = klass.new
+          assert_equal '', record.non_null_blob
+          assert_equal '', record.non_null_text
 
-          assert_nil klass.columns_hash['null_blob'].default
-          assert_nil klass.columns_hash['null_text'].default
+          assert_nil record.null_blob
+          assert_nil record.null_text
 
-          instance = klass.create!
+          record.save!
+          record.reload
 
-          assert_equal '', instance.non_null_text
-          assert_equal '', instance.non_null_blob
+          assert_equal '', record.non_null_text
+          assert_equal '', record.non_null_blob
 
-          assert_nil instance.null_text
-          assert_nil instance.null_blob
+          assert_nil record.null_text
+          assert_nil record.null_blob
         end
       end
     end
@@ -142,10 +144,11 @@ if current_adapter?(:MysqlAdapter, :Mysql2Adapter)
     def test_mysql_text_not_null_defaults_strict
       using_strict(true) do
         with_text_blob_not_null_table do |klass|
-          assert_nil klass.columns_hash['non_null_blob'].default
-          assert_nil klass.columns_hash['non_null_text'].default
-          assert_nil klass.columns_hash['null_blob'].default
-          assert_nil klass.columns_hash['null_text'].default
+          record = klass.new
+          assert_nil record.non_null_blob
+          assert_nil record.non_null_text
+          assert_nil record.null_blob
+          assert_nil record.null_text
 
           assert_raises(ActiveRecord::StatementInvalid) { klass.create }
         end

activerecord/test/schema/oracle_specific_schema.rb

@@ -32,10 +32,7 @@ create sequence test_oracle_defaults_seq minvalue 10000
       fixed_time date default TO_DATE('2004-01-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS'),
       char1 varchar2(1) default 'Y',
       char2 varchar2(50) default 'a varchar field',
-      char3 clob default 'a text field',
-      positive_integer integer default 1,
-      negative_integer integer default -1,
-      decimal_number number(3,2) default 2.78
+      char3 clob default 'a text field'
   )
   SQL
   execute "create sequence defaults_seq minvalue 10000"

activerecord/test/schema/postgresql_specific_schema.rb

@@ -32,10 +32,7 @@ ActiveRecord::Schema.define do
     char1 char(1) default 'Y',
     char2 character varying(50) default 'a varchar field',
     char3 text default 'a text field',
-    positive_integer integer default 1,
-    negative_integer integer default -1,
     bigint_default bigint default 0::bigint,
-    decimal_number decimal(3,2) default 2.78,
     multiline_default text DEFAULT '--- []
 
 '::text