1 files changed, 113 insertions, 0 deletions
diff --git a/internal/aitool/dispatch_test.go b/internal/aitool/dispatch_test.go
new file mode 100644
index 0000000..6842668
--- /dev/null
+++ b/internal/aitool/dispatch_test.go
@@ -0,0 +1,113 @@
+package aitool
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestChain(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name      string
+		preferred string
+		want      []Tool
+	}{
+		{
+			name: "default chain when empty",
+			want: []Tool{ToolOpencode, ToolHexAI, ToolClaude, ToolAmp},
+		},
+		{
+			name:      "default chain when opencode",
+			preferred: "opencode",
+			want:      []Tool{ToolOpencode, ToolHexAI, ToolClaude, ToolAmp},
+		},
+		{
+			name:      "hexai chain",
+			preferred: "hexai",
+			want:      []Tool{ToolHexAI, ToolClaude, ToolAmp},
+		},
+		{
+			name:      "claude alias chain",
+			preferred: "claude-code",
+			want:      []Tool{ToolClaude, ToolAmp},
+		},
+		{
+			name:      "amp only",
+			preferred: "amp",
+			want:      []Tool{ToolAmp},
+		},
+		{
+			name:      "unknown tool",
+			preferred: "unknown",
+			want:      nil,
+		},
+	}
+
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			got := Chain(tt.preferred)
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Fatalf("Chain(%q) = %#v, want %#v", tt.preferred, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestFirstAvailable(t *testing.T) {
+	t.Parallel()
+
+	lookPath := fakeLookPath("claude", "amp")
+	got := FirstAvailable("", lookPath)
+	if got != ToolClaude {
+		t.Fatalf("FirstAvailable() = %q, want %q", got, ToolClaude)
+	}
+}
+
+func TestFirstAvailable_NoToolsFound(t *testing.T) {
+	t.Parallel()
+
+	got := FirstAvailable("", fakeLookPath())
+	if got != "" {
+		t.Fatalf("FirstAvailable() = %q, want empty", got)
+	}
+}
+
+func TestIsAvailable_OpencodeUsesOllamaBinary(t *testing.T) {
+	t.Parallel()
+
+	if !IsAvailable(ToolOpencode, fakeLookPath("ollama")) {
+		t.Fatal("expected opencode to be available when ollama exists")
+	}
+
+	if IsAvailable(ToolOpencode, fakeLookPath("opencode")) {
+		t.Fatal("expected opencode to be unavailable when only opencode binary exists")
+	}
+}
+
+func TestAvailableChain_FiltersUnavailableTools(t *testing.T) {
+	t.Parallel()
+
+	got := AvailableChain("", fakeLookPath("hexai", "amp"))
+	want := []Tool{ToolHexAI, ToolAmp}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("AvailableChain() = %#v, want %#v", got, want)
+	}
+}
+
+func fakeLookPath(tools ...string) LookPathFunc {
+	available := make(map[string]struct{}, len(tools))
+	for _, tool := range tools {
+		available[tool] = struct{}{}
+	}
+
+	return func(file string) (string, error) {
+		if _, ok := available[file]; ok {
+			return "/usr/bin/" + file, nil
+		}
+		return "", fmt.Errorf("%s not found", file)
+	}
+}