From 133f5b827198ed43b0259ef34e1ebfd4738df459 Mon Sep 17 00:00:00 2001
From: Cassandra Wallace <cassandra.s.wallace@gmail.com>
Date: Sat, 7 Mar 2026 14:00:19 +0200
Subject: [PATCH 1/4] Add validation to prevent zero quantity line items in
 purchases (#5507)

---
 app/models/purchase.rb       | 5 +++++
 spec/models/purchase_spec.rb | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/app/models/purchase.rb b/app/models/purchase.rb
index 0b75156296..b86d6a153c 100644
--- a/app/models/purchase.rb
+++ b/app/models/purchase.rb
@@ -59,6 +59,7 @@ class Purchase < ApplicationRecord
 
   validates :amount_spent_in_cents, numericality: { greater_than: 0 }
   validate :total_equal_to_all_categories
+  validate :line_items_quantity_is_positive
   before_destroy :check_no_intervening_snapshot
 
   validates :amount_spent_on_diapers_cents, numericality: { greater_than_or_equal_to: 0 }
@@ -140,4 +141,8 @@ def check_no_intervening_snapshot
       raise "We can't delete purchases entered before #{intervening.event_time.to_date}."
     end
   end
+
+  def line_items_quantity_is_positive
+    line_items_quantity_is_at_least(1)
+  end
 end
diff --git a/spec/models/purchase_spec.rb b/spec/models/purchase_spec.rb
index 4dfee762a2..a68899a4ab 100644
--- a/spec/models/purchase_spec.rb
+++ b/spec/models/purchase_spec.rb
@@ -65,6 +65,13 @@
       expect(d).not_to be_valid
     end
 
+    it "is not valid if any line item has zero quantity" do
+      item = create(:item)
+      p = build(:purchase)
+      p.line_items.build(item_id: item.id, quantity: 0)
+      expect(p).not_to be_valid
+    end
+
     it "is valid if all categories are positive and add up to the total" do
       d = build(:purchase, amount_spent_in_cents: 1150,
         amount_spent_on_diapers_cents: 200,

From e6cfb13205387a2c72532e2070aa66debd03058a Mon Sep 17 00:00:00 2001
From: Cassandra Wallace <cassandra.s.wallace@gmail.com>
Date: Mon, 9 Mar 2026 22:50:46 +0200
Subject: [PATCH 2/4] Fix existing test that created purchase w/ 0 quantity
 items

---
 spec/queries/low_inventory_query_spec.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/spec/queries/low_inventory_query_spec.rb b/spec/queries/low_inventory_query_spec.rb
index fd7454e851..5462607b01 100644
--- a/spec/queries/low_inventory_query_spec.rb
+++ b/spec/queries/low_inventory_query_spec.rb
@@ -34,7 +34,10 @@
   context "when minimum_quantity is 0 and recommended_quantity is nil and item quantity is 0" do
     let(:item) { create :item, organization: organization }
     let(:minimum_quantity) { 0 }
-    let(:inventory_item_quantity) { 0 }
+
+    before do
+      TestInventory.create_inventory(organization, { storage_location.id => { item.id => 0 } })
+    end
 
     it { is_expected.to eq [] }
   end

From 03cd0710f6551e0957c7731fe286320cb790909a Mon Sep 17 00:00:00 2001
From: Cassandra Wallace <cassandra.s.wallace@gmail.com>
Date: Mon, 9 Mar 2026 22:58:54 +0200
Subject: [PATCH 3/4] Add test for neg quantity in purchase line items (#5507)

---
 spec/models/purchase_spec.rb | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/spec/models/purchase_spec.rb b/spec/models/purchase_spec.rb
index a68899a4ab..8accae1383 100644
--- a/spec/models/purchase_spec.rb
+++ b/spec/models/purchase_spec.rb
@@ -72,6 +72,13 @@
       expect(p).not_to be_valid
     end
 
+    it "is not valid if any line item has negative quantity" do
+      item = create(:item)
+      p = build(:purchase)
+      p.line_items.build(item_id: item.id, quantity: -1)
+      expect(p).not_to be_valid
+    end
+
     it "is valid if all categories are positive and add up to the total" do
       d = build(:purchase, amount_spent_in_cents: 1150,
         amount_spent_on_diapers_cents: 200,

From 644e2e50d4ccae939424e82d1590ea45f3c36373 Mon Sep 17 00:00:00 2001
From: Cassandra Wallace <cassandra.s.wallace@gmail.com>
Date: Sun, 15 Mar 2026 23:32:25 +0200
Subject: [PATCH 4/4] Fix lint issue & add comment to LowInventoryQuery test

---
 spec/queries/low_inventory_query_spec.rb | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/spec/queries/low_inventory_query_spec.rb b/spec/queries/low_inventory_query_spec.rb
index 5462607b01..213e43d66d 100644
--- a/spec/queries/low_inventory_query_spec.rb
+++ b/spec/queries/low_inventory_query_spec.rb
@@ -35,8 +35,10 @@
     let(:item) { create :item, organization: organization }
     let(:minimum_quantity) { 0 }
 
+    # Use TestInventory to set up inventory directly, instead of creating
+    # a purchase with 0 quantity items (which our validation now rejects).
     before do
-      TestInventory.create_inventory(organization, { storage_location.id => { item.id => 0 } })
+      TestInventory.create_inventory(organization, {storage_location.id => {item.id => 0}})
     end
 
     it { is_expected.to eq [] }