Add internal/kctl and internal/config packages with unit tests

internal/kctl/pairs_test.go

@@ -0,0 +1,48 @@
+package kctl
+
+import "testing"
+
+func TestFindNextContext_TwoWayToggle(t *testing.T) {
+	pairs := []ContextPair{
+		{Name: "env-pair-1", Contexts: []string{"ctx-a", "ctx-b"}},
+	}
+
+	next, ok := FindNextContext("ctx-a", pairs)
+	if !ok || next != "ctx-b" {
+		t.Fatalf("expected ctx-b, got %q (ok=%v)", next, ok)
+	}
+
+	next, ok = FindNextContext("ctx-b", pairs)
+	if !ok || next != "ctx-a" {
+		t.Fatalf("expected ctx-a, got %q (ok=%v)", next, ok)
+	}
+}
+
+func TestFindNextContext_Rotation(t *testing.T) {
+	pairs := []ContextPair{
+		{Name: "rotation", Contexts: []string{"a", "b", "c"}},
+	}
+
+	next, ok := FindNextContext("c", pairs)
+	if !ok || next != "a" {
+		t.Fatalf("expected wraparound to a, got %q (ok=%v)", next, ok)
+	}
+}
+
+func TestFindNextContext_NotConfigured(t *testing.T) {
+	pairs := []ContextPair{
+		{Name: "env-pair-1", Contexts: []string{"ctx-a", "ctx-b"}},
+	}
+
+	_, ok := FindNextContext("unrelated-context", pairs)
+	if ok {
+		t.Fatalf("expected ok=false for a context with no configured pair")
+	}
+}
+
+func TestFindNextContext_NoPairsConfigured(t *testing.T) {
+	_, ok := FindNextContext("ctx-a", nil)
+	if ok {
+		t.Fatalf("expected ok=false when no pairs are configured")
+	}
+}