Auth: Enhance password validation.

Increase minimum length to 20.
Check for digits, lower/upper case and special characters.

Change-Id: I7837780716487843f01ed2af97fcf30505d27ef7
diff --git a/core/auth/ui/api_test.go b/core/auth/ui/api_test.go
new file mode 100644
index 0000000..90e64be
--- /dev/null
+++ b/core/auth/ui/api_test.go
@@ -0,0 +1,19 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestPasswordInvalid(t *testing.T) {
+	errs := validatePassword("foobar")
+	if len(errs) != 2 {
+		t.Fatal(errs)
+	}
+}
+
+func TestPasswordValid(t *testing.T) {
+	errs := validatePassword("foBa2r-gdkjS1-SA0120")
+	if len(errs) != 0 {
+		t.Fatal(errs)
+	}
+}