NGSM-1569 add additional error handling when there is no active session

Signed-off-by: Jacob Salmela <jacob.salmela@hpe.com>

Author: jacobsalmela

internal/domain/misc.go

@@ -38,6 +38,13 @@ import (
 
 // List returns the inventory
 func (d *Domain) List() (inventory.Inventory, error) {
+	if d == nil {
+		return inventory.Inventory{}, fmt.Errorf("domain not initialized - no active session found. Run 'session init' to begin")
+	}
+	if d.datastore == nil {
+		return inventory.Inventory{}, fmt.Errorf("datastore not initialized - no active session found. Run 'session init' to begin")
+	}
+
 	inv, err := d.datastore.List()
 	if err != nil {
 		return inventory.Inventory{}, err