add pingcap/tidb#27816 issue

Signed-off-by: Karuppiah Natarajan <karuppiah7890@users.noreply.github.com>

pingcap/tidb/issue-27816/STORY.md

@@ -0,0 +1,162 @@
+https://github.com/pingcap/tidb/issues/27816
+
+TODO
+- migrate test-infra to testify for util/encrypt pkg
+
+
+Low Level TODO
+- 
+
+---
+
+Check which test files need migration
+
+```bash
+tidb $ rg "github.com/pingcap/check" util/encrypt/
+util/encrypt/crypt_test.go
+18:	. "github.com/pingcap/check"
+
+util/encrypt/aes_layer_test.go
+23:	"github.com/pingcap/check"
+
+util/encrypt/aes_test.go
+23:	. "github.com/pingcap/check"
+
+tidb $ rg "github.com/pingcap/check" util/encrypt/ -l
+util/encrypt/aes_layer_test.go
+util/encrypt/aes_test.go
+util/encrypt/crypt_test.go
+
+tidb $
+```
+
+So, it's three files
+
+- util/encrypt/aes_layer_test.go
+- util/encrypt/aes_test.go
+- util/encrypt/crypt_test.go
+
+---
+
+`util/encrypt/aes_test.go` seems to be like the biggest file so we can start from there I guess
+
+MIGRATING `util/encrypt/aes_test.go` NOW
+
+Okay, I see a `testEncryptSuite` being used here. I need to change it and start using individual golang tests similar to what has been done here - https://github.com/pingcap/tidb/pull/27747 by @tisonkun
+
+I need to also add some sort of `TestMain` test function and use `go.uber.org/goleak` package instead of `github.com/pingcap/tidb/util/testleak` being used in `util/encrypt/aes_test.go`, this is again similar to the migration done in https://github.com/pingcap/tidb/pull/27747
+
+TODO
+- Migrate from `github.com/pingcap/check` to `github.com/stretchr/testify`
+- Ensure all tests are in separate Golang Test functions
+- Ensure there is no usage of `github.com/pingcap/tidb/util/testleak`
+- Ensure there's a separate MainTest file
+    - Have goleak present there
+    - Ask @tikonsun if we need the extra options for the goleak
+
+
+
+```bash
+{ make failpoint-enable; go test -run ^TestTCopy$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+$ make failpoint-enable;
+$ go test -run ^TestTCopy$ github.com/pingcap/tidb/util/encrypt;
+ok  	github.com/pingcap/tidb/util/encrypt	0.525s
+$ make failpoint-disable;
+```
+
+Wow! That worked! I migrated `TestPad`!
+
+Also, previously I had this
+
+```go
+func TestTCopy(t *testing.T) {
+	s := &testEncryptSuite{}
+	s.TestPad(t)
+}
+...
+
+func (s *testEncryptSuite) TestPad(t *testing.T) {
+	...
+}
+```
+
+But I'm changing it already to
+
+```go
+func TestPad(t *testing.T) {
+	...
+}
+```
+
+and removing `TestTCopy`
+
+```bash
+tidb $ make failpoint-enable;
+tidb $ go test -run ^TestPad$ github.com/pingcap/tidb/util/encrypt;
+ok  	github.com/pingcap/tidb/util/encrypt	0.453s
+tidb $ make failpoint-disable;
+tidb $ 
+```
+
+TODO
+- Migrate TestPad [DONE]
+- Migrate TestUnpad [DONE]
+- Migrate TestAESECB [DONE]
+- Migrate TestAESEncryptWithECB [DONE]
+- Migrate TestAESDecryptWithECB [DONE]
+- Migrate TestAESEncryptWithCBC [DONE]
+- Migrate TestAESEncryptWithOFB [DONE]
+- Migrate TestAESDecryptWithOFB [DONE]
+- Migrate TestAESDecryptWithCBC [DONE]
+- Migrate TestAESEncryptWithCFB [DONE]
+- Migrate TestAESDecryptWithCFB
+- Migrate TestDeriveKeyMySQL
+
+---
+
+
+```bash
+{ make failpoint-enable; go test -run ^TestUnpad$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+tidb $ make failpoint-enable;
+tidb $ go test -run ^TestUnpad$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable;
+ok  	github.com/pingcap/tidb/util/encrypt	0.397s
+tidb $ 
+```
+
+```bash
+{ make failpoint-enable; go test -run ^TestAESECB$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+{ make failpoint-enable; go test -run ^TestAESEncryptWithECB$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+{ make failpoint-enable; go test -run ^TestAESDecryptWithECB$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+{ make failpoint-enable; go test -run ^TestAESEncryptWithCBC$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+{ make failpoint-enable; go test -run ^TestAESEncryptWithOFB$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+{ make failpoint-enable; go test -run ^TestAESDecryptWithOFB$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+{ make failpoint-enable; go test -run ^TestAESDecryptWithCBC$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```
+
+```bash
+{ make failpoint-enable; go test -run ^TestAESEncryptWithCFB$ github.com/pingcap/tidb/util/encrypt; make failpoint-disable; }
+```