diff --git a/rust/src/core/cost_pricing.rs b/rust/src/core/cost_pricing.rs
index b03174b8b5..0c70f64a06 100755
--- a/rust/src/core/cost_pricing.rs
+++ b/rust/src/core/cost_pricing.rs
@@ -915,221 +915,5 @@ impl CostUsagePricing {
 }
 
 #[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn test_normalize_codex_model() {
-        assert_eq!(CostUsagePricing::normalize_codex_model("gpt-5"), "gpt-5");
-        assert_eq!(
-            CostUsagePricing::normalize_codex_model("openai/gpt-5"),
-            "gpt-5"
-        );
-        assert_eq!(
-            CostUsagePricing::normalize_codex_model("gpt-5-codex"),
-            "gpt-5"
-        );
-    }
-
-    #[test]
-    fn test_normalize_claude_model() {
-        assert_eq!(
-            CostUsagePricing::normalize_claude_model("claude-sonnet-4-5"),
-            "claude-sonnet-4-5"
-        );
-        assert_eq!(
-            CostUsagePricing::normalize_claude_model("anthropic.claude-sonnet-4-5"),
-            "claude-sonnet-4-5"
-        );
-    }
-
-    #[test]
-    fn test_codex_cost() {
-        let cost = CostUsagePricing::codex_cost_usd("gpt-5", 1000, 0, 500);
-        assert!(cost.is_some());
-        let cost = cost.unwrap();
-        // 1000 * 1.25e-6 + 500 * 1e-5 = 0.00125 + 0.005 = 0.00625
-        assert!((cost - 0.00625).abs() < 1e-10);
-    }
-
-    #[test]
-    fn test_claude_cost() {
-        let cost = CostUsagePricing::claude_cost_usd("claude-haiku-4-5-20251001", 1000, 0, 0, 500);
-        assert!(cost.is_some());
-    }
-
-    #[test]
-    fn test_opus_4_8_cost() {
-        // Opus 4.8 bills at $5/1M input + $25/1M output (same tier as 4.5/4.6/4.7).
-        let cost = CostUsagePricing::claude_cost_usd("claude-opus-4-8", 1_000, 0, 0, 500).unwrap();
-        // 1000 * 5e-6 + 500 * 2.5e-5 = 0.005 + 0.0125 = 0.0175
-        assert!((cost - 0.0175).abs() < 1e-10);
-    }
-
-    #[test]
-    fn test_fable_5_cost() {
-        // Fable 5 bills at $10/1M input + $50/1M output.
-        let cost = CostUsagePricing::claude_cost_usd("claude-fable-5", 1_000, 0, 0, 500).unwrap();
-        // 1000 * 1e-5 + 500 * 5e-5 = 0.01 + 0.025 = 0.035
-        assert!((cost - 0.035).abs() < 1e-10);
-    }
-
-    #[test]
-    fn test_claude_input_cost_per_token() {
-        assert_eq!(
-            CostUsagePricing::claude_input_cost_per_token("claude-opus-4-8"),
-            Some(5e-6)
-        );
-        assert_eq!(
-            CostUsagePricing::claude_input_cost_per_token("claude-fable-5"),
-            Some(1e-5)
-        );
-        assert_eq!(
-            CostUsagePricing::claude_input_cost_per_token("totally-unknown-model"),
-            None
-        );
-    }
-
-    #[test]
-    fn test_format_model_name() {
-        assert_eq!(
-            CostUsagePricing::format_model_name("claude-3.5-sonnet"),
-            "Sonnet 3.5"
-        );
-        assert_eq!(
-            CostUsagePricing::format_model_name("claude-opus-4"),
-            "Opus 4"
-        );
-        assert_eq!(CostUsagePricing::format_model_name("gpt-5"), "GPT-5");
-    }
-
-    #[test]
-    fn test_gpt54_mini_cost() {
-        let cost = CostUsagePricing::codex_cost_usd("gpt-5.4-mini", 1000, 0, 500);
-        assert!(cost.is_some());
-        // 1000 * 7.5e-7 + 500 * 4.5e-6 = 0.00075 + 0.00225 = 0.003
-        assert!((cost.unwrap() - 0.003).abs() < 1e-10);
-    }
-
-    #[test]
-    fn test_gpt54_nano_cost() {
-        let cost = CostUsagePricing::codex_cost_usd("gpt-5.4-nano", 1000, 0, 500);
-        assert!(cost.is_some());
-        // 1000 * 2e-7 + 500 * 1.25e-6 = 0.0002 + 0.000625 = 0.000825
-        assert!((cost.unwrap() - 0.000825).abs() < 1e-10);
-    }
-
-    #[test]
-    fn test_normalize_gpt54_codex() {
-        assert_eq!(
-            CostUsagePricing::normalize_codex_model("gpt-5.4-mini-codex"),
-            "gpt-5.4-mini"
-        );
-    }
-
-    #[test]
-    fn test_gpt55_pricing() {
-        assert_eq!(
-            CostUsagePricing::normalize_codex_model("openai/gpt-5.5-2026-04-23"),
-            "gpt-5.5"
-        );
-        assert_eq!(
-            CostUsagePricing::normalize_codex_model("gpt-5.5-pro-2026-04-23"),
-            "gpt-5.5-pro"
-        );
-
-        let cost = CostUsagePricing::codex_cost_usd("gpt-5.5", 1000, 500, 500);
-        assert!(cost.is_some());
-        assert!((cost.unwrap() - 0.01775).abs() < 1e-10);
-    }
-
-    #[test]
-    fn test_format_gpt54_mini() {
-        assert_eq!(
-            CostUsagePricing::format_model_name("gpt-5.4-mini"),
-            "GPT-5.4 Mini"
-        );
-    }
-
-    #[test]
-    fn test_opus_4_7_cost() {
-        let cost = CostUsagePricing::claude_cost_usd("claude-opus-4-7", 1000, 0, 0, 500);
-        assert!(cost.is_some());
-    }
-
-    #[test]
-    fn test_sonnet_4_6_cost() {
-        let cost = CostUsagePricing::claude_cost_usd("claude-sonnet-4-6", 1000, 0, 0, 500);
-        assert!(cost.is_some());
-    }
-
-    #[test]
-    fn test_gpt5_pro_cost() {
-        let cost = CostUsagePricing::codex_cost_usd("gpt-5-pro", 1000, 0, 500);
-        assert!(cost.is_some());
-        // 1000 * 1.5e-5 + 500 * 1.2e-4 = 0.015 + 0.06 = 0.075
-        assert!((cost.unwrap() - 0.075).abs() < 1e-10);
-    }
-
-    #[test]
-    fn test_gpt56_standard_pricing() {
-        for (model, expected) in [
-            ("gpt-5.6-sol", 0.0332),
-            ("gpt-5.6-terra", 0.0166),
-            ("gpt-5.6-luna", 0.00664),
-        ] {
-            let cost = CostUsagePricing::codex_cost_usd(model, 1_000, 400, 1_000);
-            assert!((cost.unwrap() - expected).abs() < 1e-10, "{model}");
-        }
-    }
-
-    #[test]
-    fn test_gpt56_long_context_pricing() {
-        for (model, expected) in [
-            ("gpt-5.6-sol", 45.272001),
-            ("gpt-5.6-terra", 22.6360005),
-            ("gpt-5.6-luna", 9.0544002),
-        ] {
-            let cost = CostUsagePricing::codex_cost_usd(model, 272_001, 272_001, 1_000_000);
-            assert!((cost.unwrap() - expected).abs() < 1e-10, "{model}");
-        }
-    }
-
-    #[test]
-    fn test_gpt56_context_threshold_is_exclusive() {
-        for (model, expected) in [
-            ("gpt-5.6-sol", 0.136),
-            ("gpt-5.6-terra", 0.068),
-            ("gpt-5.6-luna", 0.0272),
-        ] {
-            let cost = CostUsagePricing::codex_cost_usd(model, 272_000, 272_000, 0);
-            assert!((cost.unwrap() - expected).abs() < 1e-10, "{model}");
-        }
-    }
-
-    #[test]
-    fn test_normalize_gpt56_aliases() {
-        for model in [
-            "gpt-5.6",
-            "openai/gpt-5.6",
-            "gpt-5.6-codex",
-            "gpt-5.6-2099-01-01",
-            "openai/gpt-5.6-codex-2099-01-01",
-        ] {
-            assert_eq!(
-                CostUsagePricing::normalize_codex_model(model),
-                "gpt-5.6-sol",
-                "{model}"
-            );
-        }
-    }
-
-    #[test]
-    fn test_codex_display_label() {
-        assert_eq!(
-            CostUsagePricing::codex_display_label("gpt-5.3-codex-spark"),
-            Some("Research Preview")
-        );
-        assert_eq!(CostUsagePricing::codex_display_label("gpt-5.4"), None);
-    }
-}
+#[path = "cost_pricing_tests.rs"]
+mod tests;
diff --git a/rust/src/core/cost_pricing_tests.rs b/rust/src/core/cost_pricing_tests.rs
new file mode 100644
index 0000000000..f0552a5505
--- /dev/null
+++ b/rust/src/core/cost_pricing_tests.rs
@@ -0,0 +1,200 @@
+use super::*;
+
+#[test]
+fn test_normalize_codex_model() {
+    assert_eq!(CostUsagePricing::normalize_codex_model("gpt-5"), "gpt-5");
+    assert_eq!(
+        CostUsagePricing::normalize_codex_model("openai/gpt-5"),
+        "gpt-5"
+    );
+    assert_eq!(
+        CostUsagePricing::normalize_codex_model("gpt-5-codex"),
+        "gpt-5"
+    );
+}
+
+#[test]
+fn test_normalize_claude_model() {
+    assert_eq!(
+        CostUsagePricing::normalize_claude_model("claude-sonnet-4-5"),
+        "claude-sonnet-4-5"
+    );
+    assert_eq!(
+        CostUsagePricing::normalize_claude_model("anthropic.claude-sonnet-4-5"),
+        "claude-sonnet-4-5"
+    );
+}
+
+#[test]
+fn test_codex_cost() {
+    let cost = CostUsagePricing::codex_cost_usd("gpt-5", 1000, 0, 500).unwrap();
+    assert!((cost - 0.00625).abs() < 1e-10);
+}
+
+#[test]
+fn test_claude_cost() {
+    assert!(
+        CostUsagePricing::claude_cost_usd("claude-haiku-4-5-20251001", 1000, 0, 0, 500).is_some()
+    );
+}
+
+#[test]
+fn test_opus_4_8_cost() {
+    let cost = CostUsagePricing::claude_cost_usd("claude-opus-4-8", 1_000, 0, 0, 500).unwrap();
+    assert!((cost - 0.0175).abs() < 1e-10);
+}
+
+#[test]
+fn test_fable_5_cost() {
+    let cost = CostUsagePricing::claude_cost_usd("claude-fable-5", 1_000, 0, 0, 500).unwrap();
+    assert!((cost - 0.035).abs() < 1e-10);
+}
+
+#[test]
+fn test_claude_input_cost_per_token() {
+    assert_eq!(
+        CostUsagePricing::claude_input_cost_per_token("claude-opus-4-8"),
+        Some(5e-6)
+    );
+    assert_eq!(
+        CostUsagePricing::claude_input_cost_per_token("claude-fable-5"),
+        Some(1e-5)
+    );
+    assert_eq!(
+        CostUsagePricing::claude_input_cost_per_token("totally-unknown-model"),
+        None
+    );
+}
+
+#[test]
+fn test_format_model_name() {
+    assert_eq!(
+        CostUsagePricing::format_model_name("claude-3.5-sonnet"),
+        "Sonnet 3.5"
+    );
+    assert_eq!(
+        CostUsagePricing::format_model_name("claude-opus-4"),
+        "Opus 4"
+    );
+    assert_eq!(CostUsagePricing::format_model_name("gpt-5"), "GPT-5");
+}
+
+#[test]
+fn test_gpt54_mini_cost() {
+    let cost = CostUsagePricing::codex_cost_usd("gpt-5.4-mini", 1000, 0, 500).unwrap();
+    assert!((cost - 0.003).abs() < 1e-10);
+}
+
+#[test]
+fn test_gpt54_nano_cost() {
+    let cost = CostUsagePricing::codex_cost_usd("gpt-5.4-nano", 1000, 0, 500).unwrap();
+    assert!((cost - 0.000825).abs() < 1e-10);
+}
+
+#[test]
+fn test_normalize_gpt54_codex() {
+    assert_eq!(
+        CostUsagePricing::normalize_codex_model("gpt-5.4-mini-codex"),
+        "gpt-5.4-mini"
+    );
+}
+
+#[test]
+fn test_gpt55_pricing() {
+    assert_eq!(
+        CostUsagePricing::normalize_codex_model("openai/gpt-5.5-2026-04-23"),
+        "gpt-5.5"
+    );
+    assert_eq!(
+        CostUsagePricing::normalize_codex_model("gpt-5.5-pro-2026-04-23"),
+        "gpt-5.5-pro"
+    );
+    let cost = CostUsagePricing::codex_cost_usd("gpt-5.5", 1000, 500, 500).unwrap();
+    assert!((cost - 0.01775).abs() < 1e-10);
+}
+
+#[test]
+fn test_format_gpt54_mini() {
+    assert_eq!(
+        CostUsagePricing::format_model_name("gpt-5.4-mini"),
+        "GPT-5.4 Mini"
+    );
+}
+
+#[test]
+fn test_opus_4_7_cost() {
+    assert!(CostUsagePricing::claude_cost_usd("claude-opus-4-7", 1000, 0, 0, 500).is_some());
+}
+
+#[test]
+fn test_sonnet_4_6_cost() {
+    assert!(CostUsagePricing::claude_cost_usd("claude-sonnet-4-6", 1000, 0, 0, 500).is_some());
+}
+
+#[test]
+fn test_gpt5_pro_cost() {
+    let cost = CostUsagePricing::codex_cost_usd("gpt-5-pro", 1000, 0, 500).unwrap();
+    assert!((cost - 0.075).abs() < 1e-10);
+}
+
+#[test]
+fn test_gpt56_standard_pricing() {
+    for (model, expected) in [
+        ("gpt-5.6-sol", 0.0332),
+        ("gpt-5.6-terra", 0.0166),
+        ("gpt-5.6-luna", 0.00664),
+    ] {
+        let cost = CostUsagePricing::codex_cost_usd(model, 1_000, 400, 1_000);
+        assert!((cost.unwrap() - expected).abs() < 1e-10, "{model}");
+    }
+}
+
+#[test]
+fn test_gpt56_long_context_pricing() {
+    for (model, expected) in [
+        ("gpt-5.6-sol", 45.272001),
+        ("gpt-5.6-terra", 22.6360005),
+        ("gpt-5.6-luna", 9.0544002),
+    ] {
+        let cost = CostUsagePricing::codex_cost_usd(model, 272_001, 272_001, 1_000_000);
+        assert!((cost.unwrap() - expected).abs() < 1e-10, "{model}");
+    }
+}
+
+#[test]
+fn test_gpt56_context_threshold_is_exclusive() {
+    for (model, expected) in [
+        ("gpt-5.6-sol", 0.136),
+        ("gpt-5.6-terra", 0.068),
+        ("gpt-5.6-luna", 0.0272),
+    ] {
+        let cost = CostUsagePricing::codex_cost_usd(model, 272_000, 272_000, 0);
+        assert!((cost.unwrap() - expected).abs() < 1e-10, "{model}");
+    }
+}
+
+#[test]
+fn test_normalize_gpt56_aliases() {
+    for model in [
+        "gpt-5.6",
+        "openai/gpt-5.6",
+        "gpt-5.6-codex",
+        "gpt-5.6-2099-01-01",
+        "openai/gpt-5.6-codex-2099-01-01",
+    ] {
+        assert_eq!(
+            CostUsagePricing::normalize_codex_model(model),
+            "gpt-5.6-sol",
+            "{model}"
+        );
+    }
+}
+
+#[test]
+fn test_codex_display_label() {
+    assert_eq!(
+        CostUsagePricing::codex_display_label("gpt-5.3-codex-spark"),
+        Some("Research Preview")
+    );
+    assert_eq!(CostUsagePricing::codex_display_label("gpt-5.4"), None);
+}