Add unit tests for CastTo, apache#920

src/Lucene.Net.Tests/Support/Util/TestCastTo.cs

@@ -0,0 +1,96 @@
+using Lucene.Net.Attributes;
+using NUnit.Framework;
+using System;
+using System.Collections.Generic;
+
+namespace Lucene.Net.Util
+{
+    /*
+     * Licensed to the Apache Software Foundation (ASF) under one or more
+     * contributor license agreements.  See the NOTICE file distributed with
+     * this work for additional information regarding copyright ownership.
+     * The ASF licenses this file to You under the Apache License, Version 2.0
+     * (the "License"); you may not use this file except in compliance with
+     * the License.  You may obtain a copy of the License at
+     *
+     *     http://www.apache.org/licenses/LICENSE-2.0
+     *
+     * Unless required by applicable law or agreed to in writing, software
+     * distributed under the License is distributed on an "AS IS" BASIS,
+     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     * See the License for the specific language governing permissions and
+     * limitations under the License.
+     */
+
+    [TestFixture]
+    public class TestCastTo : LuceneTestCase
+    {
+        public static IEnumerable<TestCaseData> TestFromSuccessCases()
+        {
+            yield return new TestCaseData((byte)1, (short)1);
+            yield return new TestCaseData((byte)1, 1);
+            yield return new TestCaseData((byte)1, 1L);
+            yield return new TestCaseData((byte)1, 1f);
+            yield return new TestCaseData((byte)1, 1d);
+            yield return new TestCaseData((short)2, (byte)2);
+            yield return new TestCaseData((short)2, 2);
+            yield return new TestCaseData((short)2, 2L);
+            yield return new TestCaseData((short)2, 2f);
+            yield return new TestCaseData((short)2, 2d);
+            yield return new TestCaseData(3, (byte)3);
+            yield return new TestCaseData(3, (short)3);
+            yield return new TestCaseData(3, 3L);
+            yield return new TestCaseData(3, 3f);
+            yield return new TestCaseData(3, 3d);
+            yield return new TestCaseData(4L, (byte)4);
+            yield return new TestCaseData(4L, (short)4);
+            yield return new TestCaseData(4L, 4);
+            yield return new TestCaseData(4L, 4f);
+            yield return new TestCaseData(4L, 4d);
+            yield return new TestCaseData(5f, (byte)5);
+            yield return new TestCaseData(5f, (short)5);
+            yield return new TestCaseData(5f, 5);
+            yield return new TestCaseData(5f, 5L);
+            yield return new TestCaseData(5f, 5d);
+            yield return new TestCaseData(6d, (byte)6);
+            yield return new TestCaseData(6d, (short)6);
+            yield return new TestCaseData(6d, 6);
+            yield return new TestCaseData(6d, 6L);
+            yield return new TestCaseData(6d, 6f);
+        }
+
+        [Test, LuceneNetSpecific]
+        [TestCaseSource(nameof(TestFromSuccessCases))]
+        public void TestFrom_Success(object value, object expected)
+        {
+            var castTo = typeof(CastTo<>).MakeGenericType(expected.GetType());
+            var from = castTo.GetMethod("From")?.MakeGenericMethod(value.GetType())
+                ?? throw new InvalidOperationException("Could not find method CastTo<T>.From<TSource>");
+            Assert.AreEqual(expected, from.Invoke(null, new[] { value }));
+        }
+
+        public static IEnumerable<TestCaseData> TestFromInvalidCastCases()
+        {
+            yield return new TestCaseData(1, "1");
+            yield return new TestCaseData(new object(), 1);
+        }
+
+        [Test, LuceneNetSpecific]
+        [TestCaseSource(nameof(TestFromInvalidCastCases))]
+        public void TestFrom_InvalidCast(object value, object expected)
+        {
+            var castTo = typeof(CastTo<>).MakeGenericType(expected.GetType());
+            var from = castTo.GetMethod("From")?.MakeGenericMethod(value.GetType())
+                ?? throw new InvalidOperationException("Could not find method CastTo<T>.From<TSource>");
+            try
+            {
+                from.Invoke(null, new[] { value });
+                Assert.Fail("Expected an exception");
+            }
+            catch
+            {
+                // ignored
+            }
+        }
+    }
+}