adding version input, adjusting tests

install.sh

@@ -27,8 +27,13 @@ echo "Parsing go version"
 # -P uses perl syntax
 DL_VERSION_RAW="$(grep "^go [0-9]+.[0-9]+" go.mod -P)"
 if [[ -z "$DL_VERSION_RAW" ]]; then
-  echo "FATAL: Unable to pull version from go.mod"
-  exit 1
+  #no go.mod file found
+  DL_VERSION_RAW=$GO_INSTALL_VERSION
+  #no version input set either
+  if [[ "$DL_VERSION_RAW" == "." ]]; then
+    echo "FATAL: No Go version found, set version input if no go.mod file is present"
+    exit 1
+  fi
 fi
 echo "Found go version: ${DL_VERSION_RAW}"