add readme on mssql testing (#6199)

plugins/database/mssql/README.md

@@ -0,0 +1,24 @@
+# Testing
+
+To run these tests, first start MSSQL in Docker. Please do make sure to view the EULA before 
+accepting it as it includes limits on the number of users per company who can be using the 
+image, and how it can be used in testing.
+
+```
+sudo docker run -e 'ACCEPT_EULA=Y' -e 'SA_PASSWORD=<YourStrong!Passw0rd>' \
+   -p 1433:1433 --name sql1 \
+   -d mcr.microsoft.com/mssql/server:2017-latest
+```
+
+Then use the following env variables for testing:
+
+```
+export VAULT_ACC=1
+export MSSQL_URL="sqlserver://SA:%3CYourStrong%21Passw0rd%3E@localhost:1433"
+```
+
+Note that the SA password passed into the Docker container differs from the one passed into the tests.
+It's the same password, but Go's libraries require it to be percent encoded.
+
+Running all the tests at once against one Docker container will likely fail because they interact with
+each other. Consider running one test at a time.

plugins/database/mssql/mssql_test.go

@@ -14,7 +14,7 @@ import (
 
 func TestMSSQL_Initialize(t *testing.T) {
 	if os.Getenv("MSSQL_URL") == "" || os.Getenv("VAULT_ACC") != "1" {
-		return
+		t.SkipNow()
 	}
 	connURL := os.Getenv("MSSQL_URL")
 
@@ -51,7 +51,7 @@ func TestMSSQL_Initialize(t *testing.T) {
 
 func TestMSSQL_CreateUser(t *testing.T) {
 	if os.Getenv("MSSQL_URL") == "" || os.Getenv("VAULT_ACC") != "1" {
-		return
+		t.SkipNow()
 	}
 	connURL := os.Getenv("MSSQL_URL")
 
@@ -92,7 +92,7 @@ func TestMSSQL_CreateUser(t *testing.T) {
 
 func TestMSSQL_RotateRootCredentials(t *testing.T) {
 	if os.Getenv("MSSQL_URL") == "" || os.Getenv("VAULT_ACC") != "1" {
-		return
+		t.SkipNow()
 	}
 	connURL := os.Getenv("MSSQL_URL")
 
@@ -131,7 +131,7 @@ func TestMSSQL_RotateRootCredentials(t *testing.T) {
 
 func TestMSSQL_RevokeUser(t *testing.T) {
 	if os.Getenv("MSSQL_URL") == "" || os.Getenv("VAULT_ACC") != "1" {
-		return
+		t.SkipNow()
 	}
 	connURL := os.Getenv("MSSQL_URL")