Warenwirtschaft: AP-42 — Rohstoff-Dichte (g/ml) für ml-Erfassung im Wareneingang

Kundenentscheid 26.08.: Rohstoffe werden in Gramm geführt, dürfen aber in ml
erfasst werden; über die Dichte ergeben sich die Gramm (100 ml Propolistinktur
× 0,79 = 79 g).

- Neues Feld ingredients.density (g/ml, optional) inkl. Feld im INCI-Formular.
- Wareneingang: Einheiten-Umschalter g/ml am Mengenfeld (nur wenn Dichte
  hinterlegt; Live-Hinweis mit Gramm-Umrechnung, Dichte kommt aus der
  Rohstoff-Suche mit). Erfassung in ml wird über die Dichte in Gramm
  umgerechnet und kanonisch als Gramm gespeichert — InventoryService und alle
  Aggregationen bleiben unverändert. purchase_unit + density_used (Snapshot)
  protokollieren die ml-Erfassung für Anzeige/Bearbeitung; Detailseite zeigt
  „790 g (= 1.000 ml)". Wareneingang-Buchung rechnet gelieferte ml ebenfalls um.
- Serverseitige Validierung: ml nur mit hinterlegter Dichte.

Migrationen add_density_* auf Dev-/Live-DB. 4 Tests, Suite 318 grün.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/Http/Controllers/Admin/Inventory/StockEntryController.php

@@ -274,7 +274,7 @@ class StockEntryController extends Controller
             })
             ->orderBy('name')
             ->limit(30)
-            ->get(['id', 'name', 'inci']);
+            ->get(['id', 'name', 'inci', 'density']);
 
         $results = $rows->map(function (Ingredient $i) {
             $text = $i->name;
@@ -282,7 +282,8 @@ class StockEntryController extends Controller
                 $text .= ' ('.$i->inci.')';
             }
 
-            return ['id' => $i->id, 'text' => $text];
+            // AP-42: Dichte mitliefern, damit die Maske die ml-Erfassung anbieten kann.
+            return ['id' => $i->id, 'text' => $text, 'density' => $i->density !== null ? (float) $i->density : null];
         })->values()->all();
 
         return response()->json(['results' => $results]);

app/Http/Requests/Inventory/StoreStockEntryRequest.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Requests\Inventory;
 
+use App\Models\Ingredient;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
 use Illuminate\Validation\Validator;
@@ -26,6 +27,7 @@ class StoreStockEntryRequest extends FormRequest
             'location_id' => ['required', 'integer', 'exists:locations,id'],
             'ordered_at' => ['required', 'date'],
             'ordered_quantity' => ['required', 'numeric', 'min:0.000001'],
+            'ordered_unit' => ['nullable', Rule::in(['gram', 'ml'])],
             'quality_id' => ['nullable', 'integer', 'exists:material_qualities,id'],
             'tax_rate_id' => ['nullable', 'integer', 'exists:tax_rates,id'],
             'price_per_kg' => ['nullable', 'numeric', 'min:0'],
@@ -67,6 +69,13 @@ class StoreStockEntryRequest extends FormRequest
                 if (empty($this->input('quality_id'))) {
                     $validator->errors()->add('quality_id', __('Bitte eine Rohstoffqualität wählen.'));
                 }
+                // AP-42: ml-Erfassung nur, wenn für den Rohstoff eine Dichte hinterlegt ist.
+                if ($this->input('ordered_unit') === 'ml') {
+                    $density = Ingredient::query()->whereKey($this->input('ingredient_id'))->value('density');
+                    if ($density === null || (float) $density <= 0) {
+                        $validator->errors()->add('ordered_quantity', __('Für diesen Rohstoff ist keine Dichte hinterlegt — bitte in Gramm erfassen oder zuerst die Dichte pflegen.'));
+                    }
+                }
                 $net = $this->input('price_per_kg');
                 $gross = $this->input('price_per_kg_gross');
                 $hasNet = is_numeric($net) && (float) $net > 0;

app/Http/Requests/Inventory/UpdateStockEntryRequest.php

@@ -2,6 +2,7 @@
 
 namespace App\Http\Requests\Inventory;
 
+use App\Models\Ingredient;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Validation\Rule;
 use Illuminate\Validation\Validator;
@@ -26,6 +27,7 @@ class UpdateStockEntryRequest extends FormRequest
             'location_id' => ['required', 'integer', 'exists:locations,id'],
             'ordered_at' => ['required', 'date'],
             'ordered_quantity' => ['required', 'numeric', 'min:0.000001'],
+            'ordered_unit' => ['nullable', Rule::in(['gram', 'ml'])],
             'quality_id' => ['nullable', 'integer', 'exists:material_qualities,id'],
             'tax_rate_id' => ['nullable', 'integer', 'exists:tax_rates,id'],
             'price_per_kg' => ['nullable', 'numeric', 'min:0'],
@@ -67,6 +69,13 @@ class UpdateStockEntryRequest extends FormRequest
                 if (empty($this->input('quality_id'))) {
                     $validator->errors()->add('quality_id', __('Bitte eine Rohstoffqualität wählen.'));
                 }
+                // AP-42: ml-Erfassung nur mit hinterlegter Dichte.
+                if ($this->input('ordered_unit') === 'ml') {
+                    $density = Ingredient::query()->whereKey($this->input('ingredient_id'))->value('density');
+                    if ($density === null || (float) $density <= 0) {
+                        $validator->errors()->add('ordered_quantity', __('Für diesen Rohstoff ist keine Dichte hinterlegt — bitte in Gramm erfassen oder zuerst die Dichte pflegen.'));
+                    }
+                }
                 $net = $this->input('price_per_kg');
                 $gross = $this->input('price_per_kg_gross');
                 $hasNet = is_numeric($net) && (float) $net > 0;

app/Http/Requests/StoreIngredientRequest.php

@@ -24,6 +24,7 @@ class StoreIngredientRequest extends FormRequest
             'pos' => ['nullable', 'integer', 'min:0', 'max:255'],
             'default_factor' => ['nullable', 'numeric', 'min:0'],
             'min_stock_alert' => ['nullable', 'numeric', 'min:0'],
+            'density' => ['nullable', 'numeric', 'min:0'],
             'material_quality_id' => ['nullable', 'integer', 'exists:material_qualities,id'],
             'tax_rate_id' => ['nullable', 'integer', 'exists:tax_rates,id'],
             'delivery_time' => ['nullable', 'string', 'max:255'],
@@ -46,6 +47,7 @@ class StoreIngredientRequest extends FormRequest
             'exclude_from_stock' => $this->boolean('exclude_from_stock'),
             'default_factor' => $this->normalizeDecimal($this->input('default_factor')),
             'min_stock_alert' => $this->normalizeDecimal($this->input('min_stock_alert')),
+            'density' => $this->normalizeDecimal($this->input('density')),
             'material_quality_id' => $this->nullIfEmpty($this->input('material_quality_id')),
             'tax_rate_id' => $this->nullIfEmpty($this->input('tax_rate_id')),
             'delivery_time_days' => $this->nullIfEmpty($this->input('delivery_time_days')),

app/Models/Ingredient.php

@@ -62,6 +62,7 @@ class Ingredient extends Model
         'pos' => 'int',
         'default_factor' => 'decimal:2',
         'min_stock_alert' => 'decimal:2',
+        'density' => 'decimal:4',
         'delivery_time_days' => 'integer',
     ];
 
@@ -77,6 +78,7 @@ class Ingredient extends Model
         'pos',
         'default_factor',
         'min_stock_alert',
+        'density',
         'exclude_from_stock',
         'material_quality_id',
         'tax_rate_id',

app/Models/StockEntry.php

@@ -23,6 +23,8 @@ class StockEntry extends Model
         'supplier_id',
         'location_id',
         'unit',
+        'purchase_unit',
+        'density_used',
         'ordered_by',
         'ordered_at',
         'ordered_quantity',
@@ -51,6 +53,7 @@ class StockEntry extends Model
             'best_before' => 'date',
             'ordered_quantity' => 'decimal:2',
             'received_quantity' => 'decimal:2',
+            'density_used' => 'decimal:4',
             'price_per_kg' => 'decimal:4',
             'price_per_kg_gross' => 'decimal:4',
             'price_total' => 'decimal:4',

app/Repositories/StockEntryRepository.php

@@ -2,6 +2,7 @@
 
 namespace App\Repositories;
 
+use App\Models\Ingredient;
 use App\Models\StockEntry;
 use App\Models\TaxRate;
 use Illuminate\Database\Eloquent\Collection;
@@ -14,6 +15,7 @@ class StockEntryRepository
     public function create(array $data): StockEntry
     {
         $data['unit'] = ($data['entry_type'] ?? '') === 'ingredient' ? 'gram' : 'piece';
+        $data = $this->applyPurchaseUnit($data);
         $data = $this->resolvePrices($data);
 
         return StockEntry::query()->create($data);
@@ -26,6 +28,7 @@ class StockEntryRepository
     {
         if (array_key_exists('entry_type', $data)) {
             $data['unit'] = ($data['entry_type'] ?? '') === 'ingredient' ? 'gram' : 'piece';
+            $data = $this->applyPurchaseUnit($data);
         }
 
         $data = $this->resolvePrices($data);
@@ -35,6 +38,44 @@ class StockEntryRepository
         return $stockEntry->fresh();
     }
 
+    /**
+     * AP-42: In ml erfasste Rohstoffmengen über die Dichte in Gramm umrechnen und
+     * kanonisch als Gramm speichern (Bestand bleibt in Gramm). purchase_unit +
+     * density_used protokollieren die Erfassungseinheit für Anzeige/Bearbeitung.
+     * Ohne hinterlegte Dichte gilt die Menge als Gramm.
+     *
+     * @param  array<string, mixed>  $data
+     * @return array<string, mixed>
+     */
+    protected function applyPurchaseUnit(array $data): array
+    {
+        $orderedUnit = $data['ordered_unit'] ?? 'gram';
+        unset($data['ordered_unit']);
+
+        if (($data['entry_type'] ?? '') !== 'ingredient') {
+            $data['purchase_unit'] = null;
+            $data['density_used'] = null;
+
+            return $data;
+        }
+
+        $data['purchase_unit'] = 'gram';
+        $data['density_used'] = null;
+
+        if ($orderedUnit === 'ml') {
+            $density = Ingredient::query()->whereKey($data['ingredient_id'] ?? null)->value('density');
+            if ($density !== null && (float) $density > 0) {
+                $data['purchase_unit'] = 'ml';
+                $data['density_used'] = (float) $density;
+                if (isset($data['ordered_quantity'])) {
+                    $data['ordered_quantity'] = round((float) $data['ordered_quantity'] * (float) $density, 2);
+                }
+            }
+        }
+
+        return $data;
+    }
+
     /**
      * Ergänzt Netto-/Brutto-Preis pro kg und den UST-Snapshot.
      * Es genügt, Netto oder Brutto anzugeben; der jeweils fehlende Wert wird
@@ -92,6 +133,12 @@ class StockEntryRepository
         $data['status'] = 'received';
         $data['received_by'] = auth()->id();
 
+        // AP-42: Wurde in ml eingekauft, wird auch die gelieferte Menge in ml erfasst
+        // und über die (beim Bestellen gespeicherte) Dichte in Gramm umgerechnet.
+        if ($stockEntry->purchase_unit === 'ml' && $stockEntry->density_used !== null && isset($data['received_quantity'])) {
+            $data['received_quantity'] = round((float) $data['received_quantity'] * (float) $stockEntry->density_used, 2);
+        }
+
         $stockEntry->update($data);
 
         return $stockEntry->fresh();

database/migrations/2026_08_26_140000_add_density_to_ingredients_and_stock_entries.php

@@ -0,0 +1,39 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * AP-42 (Kundenentscheid 26.08.2026): Rohstoffe werden in Gramm geführt, dürfen
+     * aber in ml erfasst werden. Über die hinterlegte Dichte (g/ml) ergeben sich die
+     * Gramm — z. B. 100 ml Propolistinktur (0,79 g/ml) = 79 g. Ohne Dichte gilt die
+     * Menge weiter als Gramm.
+     *
+     * Bestand bleibt kanonisch in Gramm (received_quantity/ordered_quantity), die
+     * Umrechnung passiert beim Erfassen. purchase_unit + density_used protokollieren
+     * die ml-Erfassung für Anzeige und Bearbeitung.
+     */
+    public function up(): void
+    {
+        Schema::table('ingredients', function (Blueprint $table) {
+            $table->decimal('density', 8, 4)->nullable()->after('default_factor');
+        });
+        Schema::table('stock_entries', function (Blueprint $table) {
+            $table->string('purchase_unit', 4)->nullable()->after('unit');
+            $table->decimal('density_used', 8, 4)->nullable()->after('purchase_unit');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('ingredients', function (Blueprint $table) {
+            $table->dropColumn('density');
+        });
+        Schema::table('stock_entries', function (Blueprint $table) {
+            $table->dropColumn(['purchase_unit', 'density_used']);
+        });
+    }
+};

resources/views/admin/ingredient/form.blade.php

@@ -182,6 +182,12 @@
                 <label class="form-label" for="min_stock_alert">{{ __('Meldebestand (g)') }}</label>
                 {{ Form::text('min_stock_alert', $model->min_stock_alert !== null ? formatNumber($model->min_stock_alert) : '',  array('placeholder'=>__('optional'), 'class'=>'form-control', 'id'=>'min_stock_alert')) }}
             </div>
+            <div class="form-group col-sm-3">
+                {{-- AP-42: Dichte g/ml — erlaubt die Erfassung des Wareneingangs in ml (100 ml × 0,79 = 79 g). --}}
+                <label class="form-label" for="density">{{ __('Dichte (g/ml)') }}</label>
+                {{ Form::text('density', $model->density !== null ? formatNumber($model->density) : '',  array('placeholder'=>__('z. B. 0,79 – optional'), 'class'=>'form-control', 'id'=>'density')) }}
+                <small class="form-text text-muted">{{ __('Leer = Erfassung in Gramm.') }}</small>
+            </div>
         </div>
 
         <div class="form-row">

resources/views/admin/inventory/stock-entries/_form.blade.php

@@ -21,7 +21,7 @@
         <select name="ingredient_id" id="ingredient_id" class="w-100"
             data-search-url="{{ route('admin.inventory.api.ingredients.search') }}">
             @if ($model->ingredient_id && $model->ingredient)
-                <option value="{{ $model->ingredient_id }}" selected>{{ $model->ingredient->name }}@if ($model->ingredient->inci)
+                <option value="{{ $model->ingredient_id }}" data-density="{{ $model->ingredient->density }}" selected>{{ $model->ingredient->name }}@if ($model->ingredient->inci)
                         ({{ $model->ingredient->inci }})
                     @endif
                 </option>
@@ -103,15 +103,31 @@
     @enderror
 </div>
 
+@php
+    // AP-42: in ml erfasste Rohstoffe im Formular auch in ml anzeigen (Rückrechnung
+    // über die gespeicherte Dichte); Bestand bleibt intern in Gramm.
+    $orderedIsMl = $model->purchase_unit === 'ml' && $model->density_used;
+    $orderedDisplay = $model->ordered_quantity !== null
+        ? \App\Services\Util::formatNumber($orderedIsMl ? $model->ordered_quantity / $model->density_used : $model->ordered_quantity)
+        : '';
+@endphp
 <div class="form-group">
     <label for="ordered_quantity">{{ __('Bestellte Menge') }} <span class="text-danger">*</span></label>
-    <input type="text" name="ordered_quantity" id="ordered_quantity"
-        class="form-control @error('ordered_quantity') is-invalid @enderror"
-        value="{{ old('ordered_quantity', $model->ordered_quantity !== null ? \App\Services\Util::formatNumber($model->ordered_quantity) : '') }}"
-        required>
-    <small class="text-muted">{{ __('Bei Rohstoff in Gramm, bei Verpackung in Stück.') }}</small>
+    <div class="input-group">
+        <input type="text" name="ordered_quantity" id="ordered_quantity"
+            class="form-control @error('ordered_quantity') is-invalid @enderror"
+            value="{{ old('ordered_quantity', $orderedDisplay) }}"
+            required>
+        <div class="input-group-append" id="ordered-unit-wrap" style="display:none;">
+            <select name="ordered_unit" id="ordered_unit" class="form-control">
+                <option value="gram" @selected(old('ordered_unit', $orderedIsMl ? 'ml' : 'gram') === 'gram')>g</option>
+                <option value="ml" @selected(old('ordered_unit', $orderedIsMl ? 'ml' : 'gram') === 'ml')>ml</option>
+            </select>
+        </div>
+    </div>
+    <small class="text-muted" id="ordered-quantity-hint">{{ __('Bei Rohstoff in Gramm, bei Verpackung in Stück.') }}</small>
     @error('ordered_quantity')
-        <div class="invalid-feedback">{{ $message }}</div>
+        <div class="invalid-feedback d-block">{{ $message }}</div>
     @enderror
 </div>
 

resources/views/admin/inventory/stock-entries/_scripts.blade.php

@@ -65,6 +65,44 @@
             });
         }
 
+        // AP-42: aktuelle Dichte des gewählten Rohstoffs (aus dem AJAX-Ergebnis oder
+        // — bei vorbelegtem Rohstoff — aus der data-density-Option).
+        function currentDensity() {
+            var sel = $('#ingredient_id').select2('data');
+            if (sel && sel[0] && sel[0].density != null && sel[0].density !== '') {
+                return parseFloat(sel[0].density);
+            }
+            var d = $('#ingredient_id option:selected').data('density');
+            return (d != null && d !== '') ? parseFloat(d) : null;
+        }
+
+        function applyOrderedUnit() {
+            var isIng = $('#entry_type').val() === 'ingredient';
+            $('#ordered-unit-wrap').toggle(isIng);
+
+            var density = isIng ? currentDensity() : null;
+            var hasDensity = density != null && density > 0;
+            $('#ordered_unit option[value="ml"]').prop('disabled', !hasDensity);
+            if (!hasDensity && $('#ordered_unit').val() === 'ml') {
+                $('#ordered_unit').val('gram');
+            }
+
+            var $hint = $('#ordered-quantity-hint');
+            if (!isIng) {
+                $hint.text('{{ __('Bei Verpackung in Stück.') }}');
+                return;
+            }
+            if ($('#ordered_unit').val() === 'ml' && hasDensity) {
+                var ml = parseNumber($('#ordered_quantity').val());
+                var g = ml != null ? formatNumber(ml * density) : '?';
+                $hint.text('{{ __('Erfassung in ml — entspricht ca.') }} ' + g + ' {{ __('g (Dichte') }} ' + formatNumber(density) + ' g/ml).');
+            } else if (hasDensity) {
+                $hint.text('{{ __('In Gramm — oder Einheit auf ml stellen (Dichte hinterlegt).') }}');
+            } else {
+                $hint.text('{{ __('In Gramm. Für ml-Erfassung zuerst die Dichte am Rohstoff pflegen.') }}');
+            }
+        }
+
         function parseNumber(value) {
             if (value === null || value === undefined) {
                 return null;
@@ -106,12 +144,17 @@
             toggleBlocks();
             initIngredientSelect2();
             initPackagingSelect2();
+            applyOrderedUnit();
 
             $('#entry_type').on('change', function () {
                 toggleBlocks();
+                applyOrderedUnit();
                 $('#packaging_item_id').val(null).trigger('change');
                 initPackagingSelect2();
             });
+            $('#ingredient_id').on('change', applyOrderedUnit);
+            $('#ordered_unit').on('change', applyOrderedUnit);
+            $('#ordered_quantity').on('input', applyOrderedUnit);
 
             $('#price_per_kg').on('input', recalcFromNet);
             $('#price_per_kg_gross').on('input', recalcFromGross);

resources/views/admin/inventory/stock-entries/show.blade.php

@@ -85,6 +85,9 @@
                     <span class="wawi-deflist__value">
                         @if($model->unit === 'gram')
                             {{ \App\Services\Util::formatNumber($model->ordered_quantity) }} g
+                            @if($model->purchase_unit === 'ml' && $model->density_used)
+                                <span class="text-muted">(= {{ \App\Services\Util::formatNumber($model->ordered_quantity / $model->density_used) }} ml)</span>
+                            @endif
                         @else
                             {{ \App\Services\Util::formatNumber($model->ordered_quantity, 0) }} {{ __('Stk.') }}
                         @endif
@@ -134,6 +137,9 @@
                         <span class="wawi-deflist__value">
                             @if($model->unit === 'gram')
                                 {{ \App\Services\Util::formatNumber($model->received_quantity) }} g
+                                @if($model->purchase_unit === 'ml' && $model->density_used && $model->received_quantity !== null)
+                                    <span class="text-muted">(= {{ \App\Services\Util::formatNumber($model->received_quantity / $model->density_used) }} ml)</span>
+                                @endif
                             @else
                                 {{ \App\Services\Util::formatNumber($model->received_quantity, 0) }} {{ __('Stk.') }}
                             @endif
@@ -184,13 +190,23 @@
                         @enderror
                     </div>
 
+                    @php
+                        // AP-42: Wurde in ml eingekauft, wird auch der Eingang in ml erfasst
+                        // und über die gespeicherte Dichte in Gramm umgerechnet.
+                        $receiveIsMl = $model->purchase_unit === 'ml' && $model->density_used;
+                        $receiveDefault = $receiveIsMl
+                            ? \App\Services\Util::formatNumber($model->ordered_quantity / $model->density_used)
+                            : \App\Services\Util::formatNumber($model->ordered_quantity);
+                    @endphp
                     <div class="form-group">
                         <label for="received_quantity">{{ __('Eingegangene Menge') }} <span class="text-danger">*</span></label>
                         <input type="text" name="received_quantity" id="received_quantity" required
                                class="form-control @error('received_quantity') is-invalid @enderror"
-                               value="{{ old('received_quantity', \App\Services\Util::formatNumber($model->ordered_quantity)) }}">
+                               value="{{ old('received_quantity', $receiveDefault) }}">
                         <small class="text-muted">
-                            @if($model->unit === 'gram')
+                            @if($receiveIsMl)
+                                {{ __('Angabe in ml — Umrechnung in Gramm über die Dichte') }} ({{ \App\Services\Util::formatNumber($model->density_used) }} g/ml)
+                            @elseif($model->unit === 'gram')
                                 {{ __('Angabe in Gramm') }}
                             @else
                                 {{ __('Angabe in Stück') }}

tests/Feature/IngredientDensityTest.php

@@ -0,0 +1,128 @@
+<?php
+
+use App\Models\Ingredient;
+use App\Models\Location;
+use App\Models\MaterialQuality;
+use App\Models\StockEntry;
+use App\Models\Supplier;
+use App\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+uses(TestCase::class, RefreshDatabase::class);
+
+/**
+ * AP-42: Rohstoffe werden in Gramm geführt, dürfen aber in ml erfasst werden.
+ * Über die Dichte (g/ml) ergeben sich die Gramm (100 ml Propolis × 0,79 = 79 g).
+ */
+function densAdmin(): User
+{
+    $user = User::query()->create(['email' => uniqid('dens_', true).'@test.example', 'password' => bcrypt('password')]);
+    $user->forceFill(['admin' => 7, 'confirmed' => true, 'active' => true, 'wizard' => 100, 'blocked' => false])->save();
+
+    return $user->fresh();
+}
+
+/**
+ * @return array{0: User, 1: Ingredient, 2: Location, 3: Supplier, 4: MaterialQuality}
+ */
+function densSetup(?float $density): array
+{
+    $admin = densAdmin();
+    $ingredient = Ingredient::query()->create(['name' => 'INCI-'.uniqid('', true), 'active' => true, 'pos' => 0, 'density' => $density]);
+
+    return [$admin, $ingredient, Location::factory()->create(), Supplier::factory()->create(), MaterialQuality::factory()->create()];
+}
+
+test('AP-42: ml-erfassung wird über die dichte in gramm gespeichert', function () {
+    [$admin, $ingredient, $location, $supplier, $quality] = densSetup(0.79);
+    $this->actingAs($admin, 'user');
+
+    $this->post(route('admin.inventory.stock-entries.store'), [
+        'entry_type' => 'ingredient',
+        'ingredient_id' => (string) $ingredient->id,
+        'supplier_id' => (string) $supplier->id,
+        'location_id' => (string) $location->id,
+        'quality_id' => (string) $quality->id,
+        'ordered_at' => '2026-08-01',
+        'ordered_quantity' => '100',
+        'ordered_unit' => 'ml',
+        'price_per_kg' => '10,00',
+    ])->assertRedirect(route('admin.inventory.stock-entries.index'));
+
+    $entry = StockEntry::query()->latest('id')->firstOrFail();
+    expect((float) $entry->ordered_quantity)->toBe(79.0)
+        ->and($entry->purchase_unit)->toBe('ml')
+        ->and((float) $entry->density_used)->toBe(0.79);
+});
+
+test('AP-42: gramm-erfassung bleibt unverändert', function () {
+    [$admin, $ingredient, $location, $supplier, $quality] = densSetup(0.79);
+    $this->actingAs($admin, 'user');
+
+    $this->post(route('admin.inventory.stock-entries.store'), [
+        'entry_type' => 'ingredient',
+        'ingredient_id' => (string) $ingredient->id,
+        'supplier_id' => (string) $supplier->id,
+        'location_id' => (string) $location->id,
+        'quality_id' => (string) $quality->id,
+        'ordered_at' => '2026-08-01',
+        'ordered_quantity' => '100',
+        'ordered_unit' => 'gram',
+        'price_per_kg' => '10,00',
+    ])->assertRedirect();
+
+    $entry = StockEntry::query()->latest('id')->firstOrFail();
+    expect((float) $entry->ordered_quantity)->toBe(100.0)
+        ->and($entry->purchase_unit)->toBe('gram')
+        ->and($entry->density_used)->toBeNull();
+});
+
+test('AP-42: ml-erfassung ohne hinterlegte dichte wird abgelehnt', function () {
+    [$admin, $ingredient, $location, $supplier, $quality] = densSetup(null);
+    $this->actingAs($admin, 'user');
+
+    $this->post(route('admin.inventory.stock-entries.store'), [
+        'entry_type' => 'ingredient',
+        'ingredient_id' => (string) $ingredient->id,
+        'supplier_id' => (string) $supplier->id,
+        'location_id' => (string) $location->id,
+        'quality_id' => (string) $quality->id,
+        'ordered_at' => '2026-08-01',
+        'ordered_quantity' => '100',
+        'ordered_unit' => 'ml',
+        'price_per_kg' => '10,00',
+    ])->assertSessionHasErrors('ordered_quantity');
+
+    expect(StockEntry::query()->count())->toBe(0);
+});
+
+test('AP-42: wareneingang in ml wird über die dichte in gramm gebucht', function () {
+    [$admin, $ingredient, $location, $supplier, $quality] = densSetup(0.80);
+    $this->actingAs($admin, 'user');
+
+    // Bestellung in ml (250 ml × 0,80 = 200 g)
+    $this->post(route('admin.inventory.stock-entries.store'), [
+        'entry_type' => 'ingredient',
+        'ingredient_id' => (string) $ingredient->id,
+        'supplier_id' => (string) $supplier->id,
+        'location_id' => (string) $location->id,
+        'quality_id' => (string) $quality->id,
+        'ordered_at' => '2026-08-01',
+        'ordered_quantity' => '250',
+        'ordered_unit' => 'ml',
+        'price_per_kg' => '10,00',
+    ])->assertRedirect();
+
+    $entry = StockEntry::query()->latest('id')->firstOrFail();
+
+    // Wareneingang: 250 ml geliefert => 200 g gebucht
+    $this->put(route('admin.inventory.stock-entries.receive', $entry), [
+        'received_at' => '2026-08-05',
+        'received_quantity' => '250',
+        'batch_number' => 'DENS-1',
+        'best_before' => '2030-12-31',
+    ])->assertRedirect();
+
+    expect((float) $entry->fresh()->received_quantity)->toBe(200.0);
+});