1 files changed, 65 insertions, 0 deletions
diff --git a/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
new file mode 100644
index 0000000000..aa870349be
--- /dev/null
+++ b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+class Mysql2CaseSensitivityTest < ActiveRecord::Mysql2TestCase
+  class CollationTest < ActiveRecord::Base
+  end
+
+  repair_validations(CollationTest)
+
+  def test_columns_include_collation_different_from_table
+    assert_equal "utf8_bin", CollationTest.columns_hash["string_cs_column"].collation
+    assert_equal "utf8_general_ci", CollationTest.columns_hash["string_ci_column"].collation
+  end
+
+  def test_case_sensitive
+    assert_not_predicate CollationTest.columns_hash["string_ci_column"], :case_sensitive?
+    assert_predicate CollationTest.columns_hash["string_cs_column"], :case_sensitive?
+  end
+
+  def test_case_insensitive_comparison_for_ci_column
+    CollationTest.validates_uniqueness_of(:string_ci_column, case_sensitive: false)
+    CollationTest.create!(string_ci_column: "A")
+    invalid = CollationTest.new(string_ci_column: "a")
+    queries = assert_sql { invalid.save }
+    ci_uniqueness_query = queries.detect { |q| q.match(/string_ci_column/) }
+    assert_no_match(/lower/i, ci_uniqueness_query)
+  end
+
+  def test_case_insensitive_comparison_for_cs_column
+    CollationTest.validates_uniqueness_of(:string_cs_column, case_sensitive: false)
+    CollationTest.create!(string_cs_column: "A")
+    invalid = CollationTest.new(string_cs_column: "a")
+    queries = assert_sql { invalid.save }
+    cs_uniqueness_query = queries.detect { |q| q.match(/string_cs_column/) }
+    assert_match(/lower/i, cs_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_ci_column
+    CollationTest.validates_uniqueness_of(:string_ci_column, case_sensitive: true)
+    CollationTest.create!(string_ci_column: "A")
+    invalid = CollationTest.new(string_ci_column: "A")
+    queries = assert_sql { invalid.save }
+    ci_uniqueness_query = queries.detect { |q| q.match(/string_ci_column/) }
+    assert_match(/binary/i, ci_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_cs_column
+    CollationTest.validates_uniqueness_of(:string_cs_column, case_sensitive: true)
+    CollationTest.create!(string_cs_column: "A")
+    invalid = CollationTest.new(string_cs_column: "A")
+    queries = assert_sql { invalid.save }
+    cs_uniqueness_query = queries.detect { |q| q.match(/string_cs_column/) }
+    assert_no_match(/binary/i, cs_uniqueness_query)
+  end
+
+  def test_case_sensitive_comparison_for_binary_column
+    CollationTest.validates_uniqueness_of(:binary_column, case_sensitive: true)
+    CollationTest.create!(binary_column: "A")
+    invalid = CollationTest.new(binary_column: "A")
+    queries = assert_sql { invalid.save }
+    bin_uniqueness_query = queries.detect { |q| q.match(/binary_column/) }
+    assert_no_match(/\bBINARY\b/, bin_uniqueness_query)
+  end
+end