fix: fetch payment sessions from database for persistence

The test provider was using an in-memory Map to store payment sessions,
which caused "Payment session not found" errors in several scenarios:

1. Next.js hot reload clearing the memory
2. Different execution contexts (API routes vs Payload admin)
3. Server restarts losing all sessions

This fix updates all three test provider endpoints (UI, process, status)
to fetch payment data from the database when not found in memory:

- Tries in-memory session first (fast path)
- Falls back to database query by providerId
- Creates and caches session from database payment
- Handles both string and object collection configurations

This makes the built-in test UI work reliably out of the box, without
requiring users to implement custom session management.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@xtr-dev/payload-billing",
-  "version": "0.1.18",
+  "version": "0.1.21",
   "description": "PayloadCMS plugin for billing and payment provider integrations with tracking and local testing",
   "license": "MIT",
   "type": "module",

src/providers/test.ts

@@ -242,10 +242,15 @@ export const testProvider = (testConfig: TestProviderConfig) => {
         {
           path: '/payload-billing/test/payment/:id',
           method: 'get',
-          handler: (req) => {
+          handler: async (req) => {
             // Extract payment ID from URL path
             const urlParts = req.url?.split('/') || []
-            const paymentId = urlParts[urlParts.length - 1]
+            let paymentId = urlParts[urlParts.length - 1]
+
+            // Remove query parameters if present
+            if (paymentId?.includes('?')) {
+              paymentId = paymentId.split('?')[0]
+            }
 
             if (!paymentId) {
               return new Response(JSON.stringify({ error: 'Payment ID required' }), {
@@ -263,7 +268,41 @@ export const testProvider = (testConfig: TestProviderConfig) => {
               })
             }
 
-            const session = testPaymentSessions.get(paymentId)
+            // Try to get session from memory first (for backward compatibility)
+            let session = testPaymentSessions.get(paymentId)
+
+            // If not in memory, fetch from database
+            if (!session && req.payload) {
+              try {
+                const paymentsConfig = pluginConfig.collections?.payments
+                const paymentSlug = typeof paymentsConfig === 'string' ? paymentsConfig : (paymentsConfig?.slug || 'payments')
+                const result = await req.payload.find({
+                  collection: paymentSlug,
+                  where: {
+                    providerId: {
+                      equals: paymentId
+                    }
+                  },
+                  limit: 1
+                })
+
+                if (result.docs && result.docs.length > 0) {
+                  const payment = result.docs[0] as Payment
+                  // Create session from database payment
+                  session = {
+                    id: paymentId,
+                    payment: payment,
+                    createdAt: new Date(payment.createdAt || Date.now()),
+                    status: 'pending' as PaymentOutcome
+                  }
+                  // Store in memory for future requests
+                  testPaymentSessions.set(paymentId, session)
+                }
+              } catch (error) {
+                console.error('Error fetching payment from database:', error)
+              }
+            }
+
             if (!session) {
               return new Response(JSON.stringify({ error: 'Payment session not found' }), {
                 status: 404,
@@ -322,7 +361,41 @@ export const testProvider = (testConfig: TestProviderConfig) => {
 
               const { paymentId, scenarioId, method } = validation.data!
 
-              const session = testPaymentSessions.get(paymentId)
+              // Try to get session from memory first
+              let session = testPaymentSessions.get(paymentId)
+
+              // If not in memory, fetch from database
+              if (!session && req.payload) {
+                try {
+                  const paymentsConfig = pluginConfig.collections?.payments
+                const paymentSlug = typeof paymentsConfig === 'string' ? paymentsConfig : (paymentsConfig?.slug || 'payments')
+                  const result = await req.payload.find({
+                    collection: paymentSlug,
+                    where: {
+                      providerId: {
+                        equals: paymentId
+                      }
+                    },
+                    limit: 1
+                  })
+
+                  if (result.docs && result.docs.length > 0) {
+                    const payment = result.docs[0] as Payment
+                    // Create session from database payment
+                    session = {
+                      id: paymentId,
+                      payment: payment,
+                      createdAt: new Date(payment.createdAt || Date.now()),
+                      status: 'pending' as PaymentOutcome
+                    }
+                    // Store in memory for future requests
+                    testPaymentSessions.set(paymentId, session)
+                  }
+                } catch (error) {
+                  console.error('Error fetching payment from database:', error)
+                }
+              }
+
               if (!session) {
                 return new Response(JSON.stringify({ error: 'Payment session not found' }), {
                   status: 404,
@@ -398,10 +471,15 @@ export const testProvider = (testConfig: TestProviderConfig) => {
         {
           path: '/payload-billing/test/status/:id',
           method: 'get',
-          handler: (req) => {
+          handler: async (req) => {
             // Extract payment ID from URL path
             const urlParts = req.url?.split('/') || []
-            const paymentId = urlParts[urlParts.length - 1]
+            let paymentId = urlParts[urlParts.length - 1]
+
+            // Remove query parameters if present
+            if (paymentId?.includes('?')) {
+              paymentId = paymentId.split('?')[0]
+            }
 
             if (!paymentId) {
               return new Response(JSON.stringify({ error: 'Payment ID required' }), {
@@ -419,7 +497,41 @@ export const testProvider = (testConfig: TestProviderConfig) => {
               })
             }
 
-            const session = testPaymentSessions.get(paymentId)
+            // Try to get session from memory first
+            let session = testPaymentSessions.get(paymentId)
+
+            // If not in memory, fetch from database
+            if (!session && req.payload) {
+              try {
+                const paymentsConfig = pluginConfig.collections?.payments
+                const paymentSlug = typeof paymentsConfig === 'string' ? paymentsConfig : (paymentsConfig?.slug || 'payments')
+                const result = await req.payload.find({
+                  collection: paymentSlug,
+                  where: {
+                    providerId: {
+                      equals: paymentId
+                    }
+                  },
+                  limit: 1
+                })
+
+                if (result.docs && result.docs.length > 0) {
+                  const payment = result.docs[0] as Payment
+                  // Create session from database payment
+                  session = {
+                    id: paymentId,
+                    payment: payment,
+                    createdAt: new Date(payment.createdAt || Date.now()),
+                    status: 'pending' as PaymentOutcome
+                  }
+                  // Store in memory for future requests
+                  testPaymentSessions.set(paymentId, session)
+                }
+              } catch (error) {
+                console.error('Error fetching payment from database:', error)
+              }
+            }
+
             if (!session) {
               return new Response(JSON.stringify({ error: 'Payment session not found' }), {
                 status: 404,
@@ -492,7 +604,10 @@ export const testProvider = (testConfig: TestProviderConfig) => {
 
       // Set provider ID and data
       payment.providerId = testPaymentId
-      const paymentUrl = `${baseUrl}/api/payload-billing/test/payment/${testPaymentId}`
+      // Use custom UI route if specified, otherwise use built-in UI endpoint
+      const paymentUrl = testConfig.customUiRoute
+        ? `${baseUrl}${testConfig.customUiRoute}/${testPaymentId}`
+        : `${baseUrl}/api/payload-billing/test/payment/${testPaymentId}`
       const providerData: ProviderData = {
         raw: {
           id: testPaymentId,