P3: assets' posted and scheduled depreciation, their bases, and the K-1 on the tax basis (defect 13, D-41)

Book value is cost less what the books posted; the schedule's figure is
apart. An asset's acquired date comes from its entry. Contributed
property keeps its section 723 carryover basis apart from its depreciable
basis (the lower of value and adjusted basis), with its 704(c) built-in
gain and method. The K-1 worksheet reports tax-basis capital (Form 1065
Item L) beside the book figures, leaving open what only the CPA knows.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T3gXMVt7XJPi6ens1or9Dj

crates/ledger-core/tests/assets.rs

@@ -3,7 +3,7 @@
 use chrono::NaiveDate;
 use ledger_core::{
     AccountType, AssetStatus, Currency, DepreciationMethod, Ledger, Money, NewAsset,
-    accumulated_depreciation, book_value, depreciation_schedule, disposal_amounts,
+    accumulated_scheduled_through, depreciation_schedule, disposal_amounts, scheduled_book_value,
 };
 use rust_decimal::Decimal;
 
@@ -53,7 +53,7 @@ fn van_asset(
     ledger
         .register_asset(NewAsset {
             description: "Sprinter van".to_string(),
-            purchase_date: date(2026, 1, 15),
+            in_service_date: date(2026, 1, 15),
             cost: usd(&dollars.to_string()),
             salvage_value: usd("0"),
             useful_life_months: 60,
@@ -112,7 +112,7 @@ fn salvage_value_is_never_depreciated() {
     let id = ledger
         .register_asset(NewAsset {
             description: "Machine".to_string(),
-            purchase_date: date(2026, 3, 1),
+            in_service_date: date(2026, 3, 1),
             cost: usd("50000"),
             salvage_value: usd("5000"),
             useful_life_months: 36,
@@ -133,11 +133,11 @@ fn book_value_tracks_accumulated() {
     let (mut ledger, cost, accum, expense) = test_ledger();
     let id = van_asset(&mut ledger, 60_000, cost, accum, expense);
     let asset = ledger.get_asset(id).unwrap();
-    let acc = accumulated_depreciation(asset, date(2026, 12, 31)).unwrap();
+    let acc = accumulated_scheduled_through(asset, date(2026, 12, 31)).unwrap();
     // Jan 2026 prorated 17/31 of 1000 = 548.39, then 11 full months of 1000.
     assert_eq!(acc, Decimal::new(54839, 2) + Decimal::from(11_000));
     assert_eq!(
-        book_value(asset, date(2026, 12, 31)).unwrap(),
+        scheduled_book_value(asset, date(2026, 12, 31)).unwrap(),
         Decimal::from(60_000) - acc
     );
 }
@@ -174,7 +174,7 @@ fn registration_validation() {
         .unwrap();
     let base = NewAsset {
         description: "X".to_string(),
-        purchase_date: date(2026, 1, 1),
+        in_service_date: date(2026, 1, 1),
         cost: usd("1000"),
         salvage_value: usd("0"),
         useful_life_months: 12,
@@ -222,7 +222,7 @@ fn registration_rejects_date_overflow() {
     let err = ledger
         .register_asset(NewAsset {
             description: "Time machine".to_string(),
-            purchase_date: NaiveDate::MAX,
+            in_service_date: NaiveDate::MAX,
             cost: usd("1000"),
             salvage_value: usd("0"),
             useful_life_months: 12,
@@ -240,7 +240,7 @@ fn registration_rejects_date_overflow() {
     // could still reach (P0 review round 3, S1).
     let new = |date: NaiveDate, months: u32| NewAsset {
         description: "Late machine".to_string(),
-        purchase_date: date,
+        in_service_date: date,
         cost: usd("1000"),
         salvage_value: usd("0"),
         useful_life_months: months,
@@ -270,7 +270,7 @@ fn schedule_through_purchase_date_covers_one_day() {
     let id = ledger
         .register_asset(NewAsset {
             description: "X".to_string(),
-            purchase_date: date(2026, 1, 15),
+            in_service_date: date(2026, 1, 15),
             cost: usd("62000"),
             salvage_value: usd("0"),
             useful_life_months: 62,
@@ -335,7 +335,7 @@ fn registration_rejects_wrong_typed_accounts() {
     let (mut ledger, cost, accum, expense) = test_ledger();
     let base = || NewAsset {
         description: "X".to_string(),
-        purchase_date: date(2026, 1, 15),
+        in_service_date: date(2026, 1, 15),
         cost: usd("1000"),
         salvage_value: usd("0"),
         useful_life_months: 12,
@@ -415,7 +415,7 @@ fn one_month_useful_life_is_valid() {
     let id = ledger
         .register_asset(NewAsset {
             description: "Cheap tool".to_string(),
-            purchase_date: date(2026, 3, 10),
+            in_service_date: date(2026, 3, 10),
             cost: usd("300"),
             salvage_value: usd("0"),
             useful_life_months: 1,
@@ -445,11 +445,12 @@ fn disposal_on_the_purchase_date_is_allowed() {
     assert_eq!(d.accumulated, Decimal::new(3226, 2));
     assert_eq!(d.book_value, Decimal::new(5_996_774, 2));
     assert_eq!(d.gain_loss, Decimal::new(3226, 2));
-    // The day before purchase is not a disposal.
-    assert!(matches!(
-        disposal_amounts(&asset, date(2026, 1, 14), usd("60000")),
-        Err(ledger_core::LedgerError::DisposalBeforePurchase(_))
-    ));
+    // The day before it is in service nothing has accrued (whether the
+    // company held it by then is its acquisition entry's: the ledger
+    // checks that floor, Ledger::dispose_asset).
+    let d = disposal_amounts(&asset, date(2026, 1, 14), usd("60000")).unwrap();
+    assert_eq!(d.accumulated, Decimal::ZERO);
+    assert_eq!(d.book_value, asset.cost.amount);
 }
 
 /// An asset links to the posted entry that acquired it, if that entry