diff --git a/llm/ant/ant_test.go b/llm/ant/ant_test.go
new file mode 100644
index 0000000..67cc5db
--- /dev/null
+++ b/llm/ant/ant_test.go
@@ -0,0 +1,93 @@
+package ant
+
+import (
+	"math"
+	"testing"
+)
+
+// TestCalculateCostFromTokens tests the calculateCostFromTokens function
+func TestCalculateCostFromTokens(t *testing.T) {
+	tests := []struct {
+		name                     string
+		model                    string
+		inputTokens              uint64
+		outputTokens             uint64
+		cacheReadInputTokens     uint64
+		cacheCreationInputTokens uint64
+		want                     float64
+	}{
+		{
+			name:                     "Zero tokens",
+			model:                    Claude37Sonnet,
+			inputTokens:              0,
+			outputTokens:             0,
+			cacheReadInputTokens:     0,
+			cacheCreationInputTokens: 0,
+			want:                     0,
+		},
+		{
+			name:                     "1000 input tokens, 500 output tokens",
+			model:                    Claude37Sonnet,
+			inputTokens:              1000,
+			outputTokens:             500,
+			cacheReadInputTokens:     0,
+			cacheCreationInputTokens: 0,
+			want:                     0.0105,
+		},
+		{
+			name:                     "10000 input tokens, 5000 output tokens",
+			model:                    Claude37Sonnet,
+			inputTokens:              10000,
+			outputTokens:             5000,
+			cacheReadInputTokens:     0,
+			cacheCreationInputTokens: 0,
+			want:                     0.105,
+		},
+		{
+			name:                     "With cache read tokens",
+			model:                    Claude37Sonnet,
+			inputTokens:              1000,
+			outputTokens:             500,
+			cacheReadInputTokens:     2000,
+			cacheCreationInputTokens: 0,
+			want:                     0.0111,
+		},
+		{
+			name:                     "With cache creation tokens",
+			model:                    Claude37Sonnet,
+			inputTokens:              1000,
+			outputTokens:             500,
+			cacheReadInputTokens:     0,
+			cacheCreationInputTokens: 1500,
+			want:                     0.016125,
+		},
+		{
+			name:                     "With all token types",
+			model:                    Claude37Sonnet,
+			inputTokens:              1000,
+			outputTokens:             500,
+			cacheReadInputTokens:     2000,
+			cacheCreationInputTokens: 1500,
+			want:                     0.016725,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			usage := usage{
+				InputTokens:              tt.inputTokens,
+				OutputTokens:             tt.outputTokens,
+				CacheReadInputTokens:     tt.cacheReadInputTokens,
+				CacheCreationInputTokens: tt.cacheCreationInputTokens,
+			}
+			mr := response{
+				Model: tt.model,
+				Usage: usage,
+			}
+			totalCost := mr.TotalDollars()
+			if math.Abs(totalCost-tt.want) > 0.0001 {
+				t.Errorf("totalCost = %v, want %v", totalCost, tt.want)
+			}
+		})
+	}
+}