Add FindByNameRequired throwing variant (yak: Add FindByName! throwing variant)

tests/BeforeAfter.Tests/BeforeTests.cs

@@ -339,4 +339,122 @@ public class BeforeTests
 
         DbBase.Context = null;   // cleanup
     }
+
+    // ---------------------------------------------------------------------
+    // (17) DbBase.FindRequired<T> finds the matching entity — same result as Find<T>.
+    // ---------------------------------------------------------------------
+    [Fact]
+    public void DbBase_FindRequired_T_finds_matching_entity()
+    {
+        var db = new DbContext();
+        var acme = new Client { Name = "Acme" };
+        var globex = new Client { Name = "Globex" };
+        db.Attach(acme);
+        db.Attach(globex);
+
+        var result = DbBase.FindRequired<Client>(c => c.Name == "Globex", db, "name == Globex");
+
+        Assert.Same(globex, result);
+    }
+
+    // ---------------------------------------------------------------------
+    // (18) DbBase.FindRequired<T> throws when no match is found.
+    // ---------------------------------------------------------------------
+    [Fact]
+    public void DbBase_FindRequired_T_throws_when_no_match()
+    {
+        var db = new DbContext();
+        db.Attach(new Client { Name = "Acme" });
+
+        var ex = Assert.Throws<InvalidOperationException>(() =>
+            DbBase.FindRequired<Client>(c => c.Name == "Nobody", db, "name == Nobody"));
+
+        Assert.Contains("Nobody", ex.Message);
+        Assert.Contains("no matching Client found", ex.Message);
+    }
+
+    // ---------------------------------------------------------------------
+    // (19) DbBase.FindRequired<T> throws with a useful message when no context is
+    //       configured (both explicit null and singleton null).
+    // ---------------------------------------------------------------------
+    [Fact]
+    public void DbBase_FindRequired_T_throws_when_no_context_configured()
+    {
+        DbBase.Context = null;
+
+        var ex = Assert.Throws<InvalidOperationException>(() =>
+            DbBase.FindRequired<Client>(_ => true, null, "true"));
+
+        Assert.Contains("no DbContext configured", ex.Message);
+        Assert.Contains("DbBase.Context", ex.Message);
+    }
+
+    // ---------------------------------------------------------------------
+    // (20) Client.FindByNameRequired finds the matching client by name.
+    // ---------------------------------------------------------------------
+    [Fact]
+    public void Client_FindByNameRequired_finds_by_name()
+    {
+        var db = new DbContext();
+        var acme = new Client { Name = "Acme Corp" };
+        db.Attach(acme);
+
+        var result = Client.FindByNameRequired("Acme Corp", db);
+
+        Assert.Same(acme, result);
+    }
+
+    // ---------------------------------------------------------------------
+    // (21) Client.FindByNameRequired throws when no match — message includes name.
+    // ---------------------------------------------------------------------
+    [Fact]
+    public void Client_FindByNameRequired_throws_with_name_when_not_found()
+    {
+        var db = new DbContext();
+        db.Attach(new Client { Name = "Acme Corp" });
+
+        var ex = Assert.Throws<InvalidOperationException>(() =>
+            Client.FindByNameRequired("Nobody", db));
+
+        Assert.Contains("Nobody", ex.Message);
+        Assert.Contains("no matching Client found", ex.Message);
+    }
+
+    // ---------------------------------------------------------------------
+    // (22) Client.FindByNameRequired uses Context singleton when no context arg.
+    // ---------------------------------------------------------------------
+    [Fact]
+    public void Client_FindByNameRequired_uses_Context_singleton()
+    {
+        var db = new DbContext();
+        var acme = new Client { Name = "SingletonCo" };
+        db.Attach(acme);
+
+        DbBase.Context = db;
+        try
+        {
+            var result = Client.FindByNameRequired("SingletonCo");
+            Assert.Same(acme, result);
+        }
+        finally
+        {
+            DbBase.Context = null;
+        }
+    }
+
+    // ---------------------------------------------------------------------
+    // (23) Client.FindByNameRequired throws with a useful message when the
+    //       singleton is not configured (no arg, no singleton).
+    // ---------------------------------------------------------------------
+    [Fact]
+    public void Client_FindByNameRequired_throws_with_context_hint_when_singleton_null()
+    {
+        DbBase.Context = null;
+
+        var ex = Assert.Throws<InvalidOperationException>(() =>
+            Client.FindByNameRequired("SomeBody"));
+
+        Assert.Contains("no DbContext configured", ex.Message);
+        Assert.Contains("DbBase.Context", ex.Message);
+    }
 }