Aggregate proxy collective payouts by funding source

The payout creates one expense per project allocation, but the GitHub
Sponsors CSV export groups by funding source. For dtolnay this means
11 separate ~$50 expenses on OC versus one $599 row in the CSV, making
it impossible for OC to reconcile the two.

payout_proxy_collectives now groups allocations by funding source and
creates a single aggregated expense per maintainer, matching the CSV.

Author: andrew

app/models/allocation.rb

@@ -269,7 +269,8 @@ def group_projects_by_funding_source_and_platform
   end
 
   def payout
-    project_allocations.each(&:payout)
+    project_allocations.reject(&:is_proxy_collective?).each(&:payout)
+    payout_proxy_collectives
   end
 
   def payout_open_source_collectives
@@ -281,10 +282,6 @@ def payout_open_collectives
   end
 
   def payout_proxy_collectives
-    project_allocations.select(&:is_proxy_collective?).each(&:payout)
-  end
-
-  def payout_proxy_collectives_aggregated
     # Group proxy collective allocations by funding source
     proxy_allocations = project_allocations.includes(:funding_source, :project)
       .select(&:is_proxy_collective?)

test/models/allocation_test.rb

@@ -107,7 +107,84 @@ def setup
     assert_equal 40_000, ProjectAllocation.find_by(project_id: @project1.id).amount_cents
   end
 
-  test 'payout_proxy_collectives_aggregated groups allocations by funding source' do
+  test 'payout creates one expense per funding source for proxy collectives, not one per project' do
+    funding_source = FundingSource.create!(
+      url: 'https://github.com/sponsors/dtolnay',
+      platform: 'github.com'
+    )
+
+    project1 = Project.create!(
+      url: 'https://github.com/dtolnay/syn',
+      name: 'syn',
+      licenses: ['mit'],
+      registry_names: ['crates.io'],
+      repository: { 'archived' => false },
+      funding_source: funding_source,
+      owner: { 'email' => 'dtolnay@example.com' }
+    )
+
+    project2 = Project.create!(
+      url: 'https://github.com/dtolnay/serde',
+      name: 'serde',
+      licenses: ['mit'],
+      registry_names: ['crates.io'],
+      repository: { 'archived' => false },
+      funding_source: funding_source,
+      owner: { 'email' => 'dtolnay@example.com' }
+    )
+
+    project3 = Project.create!(
+      url: 'https://github.com/dtolnay/anyhow',
+      name: 'anyhow',
+      licenses: ['mit'],
+      registry_names: ['crates.io'],
+      repository: { 'archived' => false },
+      funding_source: funding_source,
+      owner: { 'email' => 'dtolnay@example.com' }
+    )
+
+    pa1 = ProjectAllocation.create!(allocation: @allocation, project: project1, fund: @fund, funding_source: funding_source, amount_cents: 20000, score: 0.3)
+    pa2 = ProjectAllocation.create!(allocation: @allocation, project: project2, fund: @fund, funding_source: funding_source, amount_cents: 20000, score: 0.3)
+    pa3 = ProjectAllocation.create!(allocation: @allocation, project: project3, fund: @fund, funding_source: funding_source, amount_cents: 19900, score: 0.3)
+
+    proxy_collective = ProxyCollective.create!(
+      slug: 'esf-github-sponsors-dtolnay',
+      name: 'https://github.com/sponsors/dtolnay',
+      website: 'https://github.com/sponsors/dtolnay'
+    )
+
+    ProxyCollective.stubs(:find_or_create_by_website).returns(proxy_collective)
+    proxy_collective.stubs(:set_payout_method).returns(true)
+
+    expense_requests = []
+    stub_request(:post, /opencollective/).to_return do |request|
+      body = JSON.parse(request.body)
+      expense_requests << body
+      if body['query'].include?('createExpense')
+        {
+          status: 200,
+          body: { data: { createExpense: { id: '1', legacyId: 789, status: 'APPROVED', amount: 59900, currency: 'USD', description: 'test', draftKey: 'abc', payee: { slug: proxy_collective.slug } } } }.to_json,
+          headers: { 'Content-Type' => 'application/json' }
+        }
+      else
+        {
+          status: 200,
+          body: { data: { processExpense: { id: '1', status: 'APPROVED' } } }.to_json,
+          headers: { 'Content-Type' => 'application/json' }
+        }
+      end
+    end
+
+    @allocation.payout
+
+    create_expense_calls = expense_requests.select { |r| r['query'].include?('createExpense') }
+    assert_equal 1, create_expense_calls.length, "Expected 1 aggregated expense but got #{create_expense_calls.length} individual ones"
+
+    total_amount = create_expense_calls.first['variables']['expense']['items'].sum { |i| i['amount'] }
+    assert_equal 59900, total_amount, "Expected aggregated amount of 59900 cents"
+  end
+
+  test 'payout_proxy_collectives groups allocations by funding source' do
     funding_source = FundingSource.create!(
       url: 'https://github.com/sponsors/testuser',
       platform: 'github.com',
@@ -164,7 +241,7 @@ def setup
     assert_equal 10000, grouped[funding_source.id].sum(&:amount_cents)
   end
 
-  test 'payout_proxy_collectives_aggregated falls back to email when aggregated total still below minimum' do
+  test 'payout_proxy_collectives falls back to email when aggregated total still below minimum' do
     funding_source = FundingSource.create!(
       url: 'https://github.com/sponsors/testuser',
       platform: 'github.com',
@@ -215,7 +292,7 @@ def setup
       headers: { 'Content-Type' => 'application/json' }
     )
 
-    @allocation.payout_proxy_collectives_aggregated
+    @allocation.payout_proxy_collectives
 
     # Should have logged payout_skipped events with fallback message for each allocation
     pa1.reload