testdata: Include a test for askpass during signing

Signed-off-by: Morten Linderud <[email protected]>

cmd/ssh-tpm-agent/testdata/script/agent_password.txt

@@ -0,0 +1,44 @@
+# Create an askpass binary
+exec go build -o askpass-test askpass.go
+exec ./askpass-test passphrase
+
+# Env
+env SSH_ASKPASS=./askpass-test
+env SSH_ASKPASS_REQUIRE=force
+
+# ssh sign file with password
+env _ASKPASS_PASSWORD=12345
+exec ssh-tpm-agent -d --no-load &agent&
+exec ssh-tpm-keygen -N $_ASKPASS_PASSWORD
+exec ssh-tpm-add
+stdout id_ecdsa.tpm
+exec ssh-add -l
+stdout ECDSA
+exec ssh-keygen -Y sign -n file -f .ssh/id_ecdsa.pub file_to_sign.txt
+stdin file_to_sign.txt
+exec ssh-keygen -Y check-novalidate -n file -f .ssh/id_ecdsa.pub -s file_to_sign.txt.sig
+exists file_to_sign.txt.sig
+exec ssh-add -D
+rm file_to_sign.txt.sig
+rm .ssh/id_ecdsa.tpm .ssh/id_ecdsa.pub
+
+-- file_to_sign.txt --
+Hello World
+
+-- go.mod --
+module example.com/askpass
+
+-- askpass.go --
+package main
+
+import (
+  "fmt"
+  "os"
+  "strings"
+)
+
+func main() {
+  if strings.Contains(os.Args[1], "passphrase") {
+	  fmt.Println(os.Getenv("_ASKPASS_PASSWORD"))
+  }
+}