Try a simple password

.docker/docker-compose-testing.yml

@@ -26,7 +26,7 @@ services:
     image: mcr.microsoft.com/mssql/server:2019-latest
     environment:
       ACCEPT_EULA: Y
-      SA_PASSWORD: <YourStrong!Passw0rd>
+      SA_PASSWORD: sa
 
   qgis-deps:
     tty: true

.docker/docker-qgis-test.sh

@@ -91,7 +91,7 @@ echo "Importing SQL Server test data..."
 export SQLUSER=sa
 export SQLHOST=mssql
 export SQLPORT=1433
-export SQLPASSWORD='<YourStrong!Passw0rd>'
+export SQLPASSWORD=sa
 export SQLDATABASE=qgis_test
 
 export PATH=$PATH:/opt/mssql-tools/bin