1 files changed, 128 insertions, 0 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
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+++ b/activerecord/test/cases/relation/where_clause_test.rb
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+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
+
+    test "merge combines two where clauses" do
+      a = WhereClause.new([table["id"].eq(1)], [])
+      b = WhereClause.new([table["name"].eq("Sean")], [])
+      expected = WhereClause.new([table["id"].eq(1), table["name"].eq("Sean")], [])
+
+      assert_equal expected, a.merge(b)
+    end
+
+    test "merge keeps the right side, when two equality clauses reference the same column" do
+      a = WhereClause.new([table["id"].eq(1), table["name"].eq("Sean")], [])
+      b = WhereClause.new([table["name"].eq("Jim")], [])
+      expected = WhereClause.new([table["id"].eq(1), table["name"].eq("Jim")], [])
+
+      assert_equal expected, a.merge(b)
+    end
+
+    test "merge removes bind parameters matching overlapping equality clauses" do
+      a = WhereClause.new(
+        [table["id"].eq(bind_param), table["name"].eq(bind_param)],
+        [[column("id"), 1], [column("name"), "Sean"]],
+      )
+      b = WhereClause.new(
+        [table["name"].eq(bind_param)],
+        [[column("name"), "Jim"]]
+      )
+      expected = WhereClause.new(
+        [table["id"].eq(bind_param), table["name"].eq(bind_param)],
+        [[column("id"), 1], [column("name"), "Jim"]],
+      )
+
+      assert_equal expected, a.merge(b)
+    end
+
+    test "merge allows for columns with the same name from different tables" do
+      skip "This is not possible as of 4.2, and the binds do not yet contain sufficient information for this to happen"
+      # We might be able to change the implementation to remove conflicts by index, rather than column name
+    end
+
+    test "a clause knows if it is empty" do
+      assert WhereClause.empty.empty?
+      assert_not WhereClause.new(["anything"], []).empty?
+    end
+
+    test "invert cannot handle nil" do
+      where_clause = WhereClause.new([nil], [])
+
+      assert_raises ArgumentError do
+        where_clause.invert
+      end
+    end
+
+    test "invert replaces each part of the predicate with its inverse" do
+      random_object = Object.new
+      original = WhereClause.new([
+        table["id"].in([1, 2, 3]),
+        table["id"].eq(1),
+        "sql literal",
+        random_object
+      ], [])
+      expected = WhereClause.new([
+        table["id"].not_in([1, 2, 3]),
+        table["id"].not_eq(1),
+        Arel::Nodes::Not.new(Arel::Nodes::SqlLiteral.new("sql literal")),
+        Arel::Nodes::Not.new(random_object)
+      ], [])
+
+      assert_equal expected, original.invert
+    end
+
+    test "accept removes binary predicates referencing a given column" do
+      where_clause = WhereClause.new([
+        table["id"].in([1, 2, 3]),
+        table["name"].eq(bind_param),
+        table["age"].gteq(bind_param),
+      ], [
+        [column("name"), "Sean"],
+        [column("age"), 30],
+      ])
+      expected = WhereClause.new([table["age"].gteq(bind_param)], [[column("age"), 30]])
+
+      assert_equal expected, where_clause.except("id", "name")
+    end
+
+    private
+
+    def table
+      Arel::Table.new("table")
+    end
+
+    def bind_param
+      Arel::Nodes::BindParam.new
+    end
+
+    def column(name)
+      ActiveRecord::ConnectionAdapters::Column.new(name, nil, nil)
+    end
+  end
+end