1 files changed, 75 insertions, 0 deletions
diff --git a/internal/resource/dependencies_test.go b/internal/resource/dependencies_test.go
new file mode 100644
index 0000000..e298740
--- /dev/null
+++ b/internal/resource/dependencies_test.go
@@ -0,0 +1,75 @@
+package resource
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestResourceDependencies(t *testing.T) {
+	r := Resource{Type: "File", Name: "/tmp/a"}
+
+	got := r.Dependencies()
+	want := []string{"File[/tmp/a]"}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("Resource.Dependencies() = %v, want %v", got, want)
+	}
+}
+
+// TestMultiDependencies ensures a Multi flattens into each member's individual
+// ID, so depending on a Multi records a dependency on every member.
+func TestMultiDependencies(t *testing.T) {
+	m := Multi{
+		Resource{Type: "File", Name: "/tmp/a"},
+		Resource{Type: "File", Name: "/tmp/b"},
+	}
+
+	got := m.Dependencies()
+	want := []string{"File[/tmp/a]", "File[/tmp/b]"}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("Multi.Dependencies() = %v, want %v", got, want)
+	}
+}
+
+// TestRegisterWithDeps ensures Register seeds dependsOn from the variadic deps
+// and de-duplicates repeated IDs.
+func TestRegisterWithDeps(t *testing.T) {
+	ResetRepository()
+
+	res := Register("File", "/tmp/a", &mockApplier{}, "File[b]", "File[c]", "File[b]")
+
+	if _, ok := res.dependsOn["File[b]"]; !ok {
+		t.Error("expected dependency File[b]")
+	}
+	if _, ok := res.dependsOn["File[c]"]; !ok {
+		t.Error("expected dependency File[c]")
+	}
+	if len(res.dependsOn) != 2 {
+		t.Errorf("expected 2 unique dependencies, got %d: %v", len(res.dependsOn), res.dependsOn)
+	}
+}
+
+func TestRegisterNoDeps(t *testing.T) {
+	ResetRepository()
+
+	res := Register("File", "/tmp/a", &mockApplier{})
+	if res.dependsOn == nil {
+		t.Error("expected dependsOn to be initialized, got nil")
+	}
+	if len(res.dependsOn) != 0 {
+		t.Errorf("expected no dependencies, got %v", res.dependsOn)
+	}
+}
+
+// TestSortedDependsOn ensures dependency IDs are returned sorted for stable log
+// output regardless of insertion/map order.
+func TestSortedDependsOn(t *testing.T) {
+	ResetRepository()
+
+	res := Register("File", "/tmp/a", &mockApplier{}, "File[c]", "File[a]", "File[b]")
+
+	got := res.sortedDependsOn()
+	want := []string{"File[a]", "File[b]", "File[c]"}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("sortedDependsOn() = %v, want %v", got, want)
+	}
+}