diff --git a/spec/ssh_scan_api/target_validator_spec.rb b/spec/ssh_scan_api/target_validator_spec.rb
index 2c083ab..e4786dc 100644
--- a/spec/ssh_scan_api/target_validator_spec.rb
+++ b/spec/ssh_scan_api/target_validator_spec.rb
@@ -81,10 +81,14 @@
     expect(target_validator.invalid_char?("1")).to be false
     expect(target_validator.invalid_char?(":")).to be false
     expect(target_validator.invalid_char?(".")).to be false
+    expect(target_validator.invalid_char?(" ")).to be true
+    expect(target_validator.invalid_char?("|")).to be true
+    expect(target_validator.invalid_char?("&")).to be true
+    expect(target_validator.invalid_char?(";")).to be true
 
     # parent valid?/invalid? checking of the same thing (but as a substring)
     expect(target_validator.invalid?("http://mywebsite")).to be true
     expect(target_validator.valid?("a.b.c")).to be true
   end
 
-end
\ No newline at end of file
+end