Add lightweight EF Core provider contrast sample

.github/workflows/build-samples.yml

@@ -30,6 +30,7 @@ on:
       - "ef-core/advanced-modeling-performance/**"
       - "ef-core/modern-data-access-dotnet/**"
       - "ef-core/multitenancy-softdelete-auditing/**"
+      - "ef-core/testing-sqlite-inmemory-vs-inmemory/**"
       - ".github/workflows/build-samples.yml"
 
   pull_request:
@@ -60,6 +61,7 @@ on:
       - "ef-core/advanced-modeling-performance/**"
       - "ef-core/modern-data-access-dotnet/**"
       - "ef-core/multitenancy-softdelete-auditing/**"
+      - "ef-core/testing-sqlite-inmemory-vs-inmemory/**"
       - ".github/workflows/build-samples.yml"
 
   workflow_dispatch:
@@ -1870,3 +1872,143 @@ jobs:
             exit 1
           fi
 
+  test-ef-core-provider-contrast:
+    name: Test EF Core provider contrast sample
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v5
+
+      - name: Install .NET 10 SDK
+        uses: actions/setup-dotnet@v5
+        with:
+          dotnet-version: "10.0.x"
+
+      - name: Restore
+        run: >
+          dotnet restore
+          ef-core/testing-sqlite-inmemory-vs-inmemory/EfCoreProviderContrastMinimal.slnx
+
+      - name: Build
+        run: >
+          dotnet build
+          ef-core/testing-sqlite-inmemory-vs-inmemory/EfCoreProviderContrastMinimal.slnx
+          --configuration Release
+          --no-restore
+
+      - name: Test
+        run: >
+          dotnet test
+          ef-core/testing-sqlite-inmemory-vs-inmemory/EfCoreProviderContrastMinimal.slnx
+          --configuration Release
+          --no-build
+
+      - name: Verify EF Core provider baseline
+        shell: bash
+        run: |
+          project="ef-core/testing-sqlite-inmemory-vs-inmemory/src/EfCoreProviderContrastMinimal/EfCoreProviderContrastMinimal.csproj"
+
+          test "$(
+            grep \
+              --count \
+              '<PackageReference' \
+              "${project}"
+          )" = "2"
+
+          grep \
+            --fixed-strings \
+            'Include="Microsoft.EntityFrameworkCore.InMemory"' \
+            "${project}"
+
+          grep \
+            --fixed-strings \
+            'Include="Microsoft.EntityFrameworkCore.Sqlite"' \
+            "${project}"
+
+          test "$(
+            grep \
+              --count \
+              'Version="10.0.11"' \
+              "${project}"
+          )" = "2"
+
+      - name: Verify exact provider-contrast output
+        shell: bash
+        run: |
+          output="$(
+            dotnet run \
+              --project ef-core/testing-sqlite-inmemory-vs-inmemory/src/EfCoreProviderContrastMinimal/EfCoreProviderContrastMinimal.csproj \
+              --configuration Release \
+              --no-build
+          )"
+
+          expected="$(
+            printf '%s\n' \
+              'EF Core Test Provider Contrast Lab' \
+              'Unique index: InMemory=accepted | SQLite=rejected' \
+              'Foreign key: InMemory=accepted | SQLite=rejected' \
+              'Transaction: InMemory=unsupported | SQLite=rollback-ok' \
+              'Database cascade: InMemory=orphan-remains | SQLite=child-removed' \
+              'Guidance: relational behavior -> production provider when practical; SQLite remains a test double.'
+          )"
+
+          printf '%s\n' "${output}"
+
+          if [[ "${output}" != "${expected}" ]]; then
+            echo "Unexpected provider-contrast output."
+            exit 1
+          fi
+
+      - name: Verify provider-contrast boundaries
+        shell: bash
+        run: |
+          sample="ef-core/testing-sqlite-inmemory-vs-inmemory"
+
+          grep -R \
+            --include='*.cs' \
+            --include='*.csproj' \
+            --fixed-strings \
+            'Foreign Keys=True' \
+            "${sample}/src"
+
+          grep -R \
+            --include='*.cs' \
+            --include='*.csproj' \
+            --fixed-strings \
+            'InMemoryDatabaseRoot' \
+            "${sample}/src"
+
+          if grep -R \
+              --include='*.cs' \
+              --include='*.csproj' \
+              -E \
+              'TransactionIgnoredWarning|BenchmarkDotNet|Stopwatch' \
+              "${sample}/src"; then
+            echo "Unexpected ignored-transaction or benchmark code found."
+            exit 1
+          fi
+
+      - name: Verify no generated database artifacts
+        shell: bash
+        run: |
+          if find \
+              ef-core/testing-sqlite-inmemory-vs-inmemory \
+              -type f \
+              \( \
+                -name '*.db' \
+                -o -name '*.sqlite' \
+                -o -name '*.sqlite3' \
+              \) \
+              -print \
+              -quit |
+              grep \
+                --quiet \
+                .; then
+            echo "Generated SQLite database file found."
+            exit 1
+          fi
+

README.md

@@ -35,6 +35,7 @@ Each sample folder contains a focused implementation of one tutorial topic. The
 | [`ef-core/advanced-modeling-performance`](ef-core/advanced-modeling-performance/) | Focused .NET 10 / EF Core 10 relational-data companion demonstrating DTO projection, no-tracking reads, a compiled hot-path query, named soft-delete filtering, ExecuteUpdate, ExecuteDelete, and explicit change-tracker caveats with deterministic SQLite tests | [EF Core Advanced Modeling & Performance: Owned Types, Converters, JSON/Temporal Tables, Compiled Queries](https://www.dotnet-guide.com/tutorials/ef-core/advanced-modeling-performance/) |
 | [`ef-core/modern-data-access-dotnet`](ef-core/modern-data-access-dotnet/) | Focused .NET 10 / EF Core 10 relationship-loading companion demonstrating one-to-many and many-to-many modeling, an intentional N+1 baseline, eager and filtered Include, split-query loading, explicit loading, SELECT-command counting, and deterministic SQLite verification | [EF Core 8 Fundamentals: Modern Data Access with .NET 8](https://www.dotnet-guide.com/tutorials/ef-core/modern-data-access-dotnet/) |
 | [`ef-core/multitenancy-softdelete-auditing`](ef-core/multitenancy-softdelete-auditing/) | Focused .NET 10 / EF Core 10 multi-tenant data guardrail companion demonstrating fail-closed tenant filtering, named soft-delete filtering, tenant-scoped composite identity, SaveChanges interception, automatic audit metadata, selective deleted-record access, cross-tenant mutation rejection, and deterministic SQLite isolation tests | [EF Core 8 Multi-Tenancy: Tenant Isolation, Soft Deletes, Audit Trails & Query Filters](https://www.dotnet-guide.com/tutorials/ef-core/multitenancy-softdelete-auditing/) |
+| [`ef-core/testing-sqlite-inmemory-vs-inmemory`](ef-core/testing-sqlite-inmemory-vs-inmemory/) | Focused .NET 10 / EF Core 10 provider-contrast companion demonstrating how SQLite in-memory and the EF Core InMemory provider differ on unique constraints, foreign keys, transactions, and database-side cascades while explicitly treating SQLite as a test double rather than production-provider parity | [EF Core Testing: SQLite In-Memory vs InMemory Provider — Which One Can You Actually Trust?](https://www.dotnet-guide.com/tutorials/ef-core/testing-sqlite-inmemory-vs-inmemory/) |
 
 ## Companion articles
 - [Common Microsoft.Extensions.AI mistakes](https://www.dotnet-guide.com/articles/dotnet-ai/microsoft-extensions-ai-common-mistakes/)
@@ -514,7 +515,7 @@ tutorials/
 |           `-- EfCoreRelationshipsMinimal.Tests/
 |               |-- EfCoreRelationshipsMinimal.Tests.csproj
 |               `-- EfCoreRelationshipsTests.cs
-|   `-- multitenancy-softdelete-auditing/
+|   |-- multitenancy-softdelete-auditing/
 |       |-- EfCoreTenantGuardrailsMinimal.slnx
 |       |-- README.md
 |       |-- src/
@@ -538,6 +539,26 @@ tutorials/
 |           `-- EfCoreTenantGuardrailsMinimal.Tests/
 |               |-- EfCoreTenantGuardrailsMinimal.Tests.csproj
 |               `-- TenantGuardrailTests.cs
+|   `-- testing-sqlite-inmemory-vs-inmemory/
+|       |-- EfCoreProviderContrastMinimal.slnx
+|       |-- README.md
+|       |-- src/
+|       |   `-- EfCoreProviderContrastMinimal/
+|       |       |-- EfCoreProviderContrastMinimal.csproj
+|       |       |-- Program.cs
+|       |       |-- Data/
+|       |       |   `-- ProviderDbContext.cs
+|       |       |-- Models/
+|       |       |   `-- ProviderModels.cs
+|       |       |-- Providers/
+|       |       |   |-- InMemoryTestDatabase.cs
+|       |       |   `-- SqliteTestDatabase.cs
+|       |       `-- Services/
+|       |           `-- ProviderContrast.cs
+|       `-- tests/
+|           `-- EfCoreProviderContrastMinimal.Tests/
+|               |-- EfCoreProviderContrastMinimal.Tests.csproj
+|               `-- ProviderContrastTests.cs
 |-- .github/
 |   `-- workflows/
 |       `-- build-samples.yml

ef-core/testing-sqlite-inmemory-vs-inmemory/EfCoreProviderContrastMinimal.slnx

@@ -0,0 +1,4 @@
+<Solution>
+  <Project Path="src/EfCoreProviderContrastMinimal/EfCoreProviderContrastMinimal.csproj" />
+  <Project Path="tests/EfCoreProviderContrastMinimal.Tests/EfCoreProviderContrastMinimal.Tests.csproj" />
+</Solution>