guide changes

services/staffAssignment_test.go

@@ -0,0 +1,54 @@
+package services
+
+import "testing"
+
+/*
+Assignment has one failure mode worth defending against, and it is silent.
+
+Taking somebody off a branch is a legitimate thing to do, and it is expressed as
+`locationid` 0. But a body that lost the field, a form that posted a blank, or a
+client that dropped it all arrive as 0 too — so inferring "unassign" from the
+zero would let a network hiccup quietly turn somebody out of their shop. The
+person would keep signing in and keep being told "No store assigned", and
+nothing would say why.
+*/
+
+func TestUnassigningMustBeAskedForExplicitly(t *testing.T) {
+	if _, err := ResolveAssignment(0, false); err == nil {
+		t.Fatal("a missing locationid was treated as a request to unassign")
+	}
+}
+
+func TestAnExplicitUnassignIsHonoured(t *testing.T) {
+	location, err := ResolveAssignment(0, true)
+	if err != nil {
+		t.Fatalf("an explicit unassign was refused: %v", err)
+	}
+	if location != 0 {
+		t.Fatalf("want 0, got %d", location)
+	}
+}
+
+// The caller said what they wanted. Preferring a leftover id would be the same
+// silent guess, running the other way.
+func TestUnassignBeatsALeftoverBranchId(t *testing.T) {
+	location, err := ResolveAssignment(1172, true)
+	if err != nil || location != 0 {
+		t.Fatalf("want 0 with no error, got %d / %v", location, err)
+	}
+}
+
+func TestANamedBranchPassesThrough(t *testing.T) {
+	location, err := ResolveAssignment(1172, false)
+	if err != nil || location != 1172 {
+		t.Fatalf("want 1172 with no error, got %d / %v", location, err)
+	}
+}
+
+// A negative id is not a branch and is not an unassign — it is a bug upstream,
+// and it should stop here rather than be rounded into either.
+func TestANegativeBranchIdIsRefused(t *testing.T) {
+	if _, err := ResolveAssignment(-3, false); err == nil {
+		t.Fatal("a negative locationid was accepted")
+	}
+}