feat: add skill tree system with 2 branches per class

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

entity/skill_tree_test.go

@@ -0,0 +1,148 @@
+package entity
+
+import "testing"
+
+func TestGetBranches(t *testing.T) {
+	classes := []Class{ClassWarrior, ClassMage, ClassHealer, ClassRogue}
+	for _, c := range classes {
+		branches := GetBranches(c)
+		if len(branches) != 2 {
+			t.Errorf("expected 2 branches for %s, got %d", c, len(branches))
+		}
+		for i, b := range branches {
+			if b.Name == "" {
+				t.Errorf("branch %d for %s has empty name", i, c)
+			}
+			for j, node := range b.Nodes {
+				if node.Name == "" {
+					t.Errorf("node %d in branch %d for %s has empty name", j, i, c)
+				}
+				if node.Value <= 0 {
+					t.Errorf("node %d in branch %d for %s has non-positive value %d", j, i, c, node.Value)
+				}
+			}
+		}
+	}
+}
+
+func TestAllocateSkillPoint(t *testing.T) {
+	ps := NewPlayerSkills()
+	ps.Points = 1
+
+	err := ps.Allocate(0, ClassWarrior)
+	if err != nil {
+		t.Fatalf("unexpected error on first allocation: %v", err)
+	}
+	if ps.BranchIndex != 0 {
+		t.Errorf("expected BranchIndex 0, got %d", ps.BranchIndex)
+	}
+	if ps.Allocated != 1 {
+		t.Errorf("expected Allocated 1, got %d", ps.Allocated)
+	}
+}
+
+func TestCannotSwitchBranch(t *testing.T) {
+	ps := NewPlayerSkills()
+	ps.Points = 2
+
+	err := ps.Allocate(0, ClassWarrior)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	err = ps.Allocate(1, ClassWarrior)
+	if err == nil {
+		t.Fatal("expected error when switching branch, got nil")
+	}
+}
+
+func TestCannotAllocateWithoutPoints(t *testing.T) {
+	ps := NewPlayerSkills()
+	ps.Points = 0
+
+	err := ps.Allocate(0, ClassWarrior)
+	if err == nil {
+		t.Fatal("expected error when no points available, got nil")
+	}
+}
+
+func TestFullyAllocated(t *testing.T) {
+	ps := NewPlayerSkills()
+	ps.Points = 4
+
+	for i := 0; i < 3; i++ {
+		err := ps.Allocate(0, ClassWarrior)
+		if err != nil {
+			t.Fatalf("unexpected error on allocation %d: %v", i+1, err)
+		}
+	}
+
+	err := ps.Allocate(0, ClassWarrior)
+	if err == nil {
+		t.Fatal("expected error when fully allocated, got nil")
+	}
+}
+
+func TestSkillBonuses(t *testing.T) {
+	// Warrior Tank branch: DEF+3, MaxHP+20, DEF+5
+	ps := NewPlayerSkills()
+	ps.Points = 3
+	for i := 0; i < 3; i++ {
+		if err := ps.Allocate(0, ClassWarrior); err != nil {
+			t.Fatalf("allocate error: %v", err)
+		}
+	}
+
+	if got := ps.GetDEFBonus(ClassWarrior); got != 8 {
+		t.Errorf("expected DEF bonus 8 (3+5), got %d", got)
+	}
+	if got := ps.GetMaxHPBonus(ClassWarrior); got != 20 {
+		t.Errorf("expected MaxHP bonus 20, got %d", got)
+	}
+	if got := ps.GetATKBonus(ClassWarrior); got != 0 {
+		t.Errorf("expected ATK bonus 0 for Tank, got %d", got)
+	}
+
+	// Warrior Berserker branch: ATK+4, SkillPower+20, ATK+6
+	ps2 := NewPlayerSkills()
+	ps2.Points = 3
+	for i := 0; i < 3; i++ {
+		if err := ps2.Allocate(1, ClassWarrior); err != nil {
+			t.Fatalf("allocate error: %v", err)
+		}
+	}
+	if got := ps2.GetATKBonus(ClassWarrior); got != 10 {
+		t.Errorf("expected ATK bonus 10 (4+6), got %d", got)
+	}
+	if got := ps2.GetSkillPower(ClassWarrior); got != 20 {
+		t.Errorf("expected SkillPower bonus 20, got %d", got)
+	}
+}
+
+func TestNilPlayerSkillsBonuses(t *testing.T) {
+	var ps *PlayerSkills
+	if got := ps.GetATKBonus(ClassWarrior); got != 0 {
+		t.Errorf("expected 0 ATK bonus from nil skills, got %d", got)
+	}
+	if got := ps.GetDEFBonus(ClassWarrior); got != 0 {
+		t.Errorf("expected 0 DEF bonus from nil skills, got %d", got)
+	}
+}
+
+func TestPartialAllocation(t *testing.T) {
+	// Rogue Assassin: ATK+5, CritChance+15, ATK+8
+	// Allocate only 2 points: should get ATK+5 and CritChance+15
+	ps := NewPlayerSkills()
+	ps.Points = 2
+	for i := 0; i < 2; i++ {
+		if err := ps.Allocate(0, ClassRogue); err != nil {
+			t.Fatalf("allocate error: %v", err)
+		}
+	}
+	if got := ps.GetATKBonus(ClassRogue); got != 5 {
+		t.Errorf("expected ATK bonus 5, got %d", got)
+	}
+	if got := ps.GetCritChance(ClassRogue); got != 15 {
+		t.Errorf("expected CritChance bonus 15, got %d", got)
+	}
+}