2 files changed, 43 insertions, 8 deletions
diff --git a/activerecord/test/cases/relation/where_clause_test.rb b/activerecord/test/cases/relation/where_clause_test.rb
new file mode 100644
index 0000000000..66e2f3ab48
--- /dev/null
+++ b/activerecord/test/cases/relation/where_clause_test.rb
@@ -0,0 +1,41 @@
+require "cases/helper"
+
+class ActiveRecord::Relation
+  class WhereClauseTest < ActiveRecord::TestCase
+    test "+ combines two where clauses" do
+      first_clause = WhereClause.new([table["id"].eq(bind_param)], [["id", 1]])
+      second_clause = WhereClause.new([table["name"].eq(bind_param)], [["name", "Sean"]])
+      combined = WhereClause.new(
+        [table["id"].eq(bind_param), table["name"].eq(bind_param)],
+        [["id", 1], ["name", "Sean"]],
+      )
+
+      assert_equal combined, first_clause + second_clause
+    end
+
+    test "+ is associative, but not commutative" do
+      a = WhereClause.new(["a"], ["bind a"])
+      b = WhereClause.new(["b"], ["bind b"])
+      c = WhereClause.new(["c"], ["bind c"])
+
+      assert_equal a + (b + c), (a + b) + c
+      assert_not_equal a + b, b + a
+    end
+
+    test "an empty where clause is the identity value for +" do
+      clause = WhereClause.new([table["id"].eq(bind_param)], [["id", 1]])
+
+      assert_equal clause, clause + WhereClause.empty
+    end
+
+    private
+
+    def table
+      Arel::Table.new("table")
+    end
+
+    def bind_param
+      Arel::Nodes::BindParam.new
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation_test.rb b/activerecord/test/cases/relation_test.rb
index f7cb471984..75d74ddc7b 100644
--- a/activerecord/test/cases/relation_test.rb
+++ b/activerecord/test/cases/relation_test.rb
@@ -177,14 +177,8 @@ module ActiveRecord
     end
 
     test 'relations can be created with a values hash' do
-      relation = Relation.new(FakeKlass, :b, nil, where: [:foo])
-      assert_equal [:foo], relation.where_values
-    end
-
-    test 'merging a single where value' do
-      relation = Relation.new(FakeKlass, :b, nil)
-      relation.merge!(where: :foo)
-      assert_equal [:foo], relation.where_values
+      relation = Relation.new(FakeKlass, :b, nil, select: [:foo])
+      assert_equal [:foo], relation.select_values
     end
 
     test 'merging a hash interpolates conditions' do