fix: Calculate depreciation_amount accurately

[GangaManoj]

Proposed Changes

• While modifying the Depreciation Schedule of an Asset after its sale, the Depreciation Amount is not calculated correctly if Depreciation Entries have been posted for it already. This PR ensures that the Depreciation Amount calculated will be accurate.

Example

Initial Asset Value = Rs 100,000
Expected Value After Useful Life = Rs 10,000
Number of Depreciation = 3
Frequency of Depreciation = 12

Before:

On selling the Asset on 31/12/2021, the Depreciation Amount for the second row should have been 30,000, but instead it's being calculated incorrectly as 20,000.

After:

• If the asset is then returned, the Depreciation Schedule should be reset, but the Depreciation Amount for subsequent rows are not being calculated accurately. This PR fixes that as well.

Example

Before:

On returning the Asset, the Depreciation Amount for the third row should have been 30,000, but instead it's being calculated incorrectly as -30,000.

After:

• If an Asset was set to be sold in the future on the day it was scheduled to be depreciated, once the Asset gets returned, the Depreciation Entry posted on its sale would not be reversed, even if the posting date for the Credit Note is in the future. This PR adds an extra condition to let the Depreciation Entry be cancelled in cases like this.

Explanation

If this Asset is set to be sold on 31-12-2021(which is in the future right now), an additional Depreciation Entry would be made for that date. On returning this Asset, the Depreciation Schedule should be reset and the Depreciation Entry posted on its sale should be reversed, but because the sale was made on the scheduled date for depreciation, the Depreciation Entry does not get reversed.

With the new condition, the Depreciation Entry made on sale will be reversed if the sale was set to happen in the future(i.e. if the Posting Date for the Sales Invoice is in the future) but gets returned, even if the date of sale = scheduled date for depreciation.

• Add more tests for Depreciation Schedule.
• Categorise tests into test suites.

[codecov]

Codecov Report

Merging #27585 (7681600) into develop (c8d0d9e) will increase coverage by 0.25%.
The diff coverage is 84.09%.

@@             Coverage Diff             @@
##           develop   #27585      +/-   ##
===========================================
+ Coverage    55.24%   55.50%   +0.25%     
===========================================
  Files         1255     1248       -7     
  Lines        67935    67753     -182     
===========================================
+ Hits         37534    37605      +71     
+ Misses       30401    30148     -253     

Impacted Files	Coverage Δ
erpnext/accounts/doctype/gl_entry/gl_entry.py	73.77% <ø> (ø)
erpnext/regional/india/utils.py	64.47% <0.00%> (-1.39%)	⬇️
...xt/accounts/doctype/sales_invoice/sales_invoice.py	78.76% <80.00%> (+2.09%)	⬆️
erpnext/assets/doctype/asset/asset.py	74.19% <88.00%> (+2.58%)	⬆️
...xt/accounts/doctype/journal_entry/journal_entry.py	68.27% <100.00%> (+0.04%)	⬆️
erpnext/stock/report/stock_ageing/stock_ageing.py	89.92% <0.00%> (-3.60%)	⬇️
...eport/item_variant_details/item_variant_details.py	84.52% <0.00%> (-3.58%)	⬇️
...xt/stock/report/stock_analytics/stock_analytics.py	91.08% <0.00%> (-2.98%)	⬇️
erpnext/stock/reorder_item.py	75.42% <0.00%> (-2.55%)	⬇️
...wise_balance_history/batch_wise_balance_history.py	91.52% <0.00%> (-1.70%)	⬇️
... and 42 more

[blewsky]

Will that also fix #27431 ?

[nextchamp-saqib]

@Mergifyio backport version-13-hotfix

[mergify]

backport version-13-hotfix

✅ Backports have been created

• #28718 fix: Calculate depreciation_amount accurately (backport #27585) has been created for branch version-13-hotfix