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diff --git a/src/test/java/org/apache/commons/lang3/concurrent/ThresholdCircuitBreakerTest.java b/src/test/java/org/apache/commons/lang3/concurrent/ThresholdCircuitBreakerTest.java
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+++ b/src/test/java/org/apache/commons/lang3/concurrent/ThresholdCircuitBreakerTest.java
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+/*
+ * 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.
+ */
+package org.apache.commons.lang3.concurrent;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.apache.commons.lang3.AbstractLangTest;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test class for {@code ThresholdCircuitBreaker}.
+ */
+public class ThresholdCircuitBreakerTest extends AbstractLangTest {
+
+    /**
+     * Threshold used in tests.
+     */
+    private static final long threshold = 10L;
+
+    private static final long zeroThreshold = 0L;
+
+    /**
+     * Tests that the threshold is working as expected when incremented and no exception is thrown.
+     */
+    @Test
+    public void testThreshold() {
+        final ThresholdCircuitBreaker circuit = new ThresholdCircuitBreaker(threshold);
+        circuit.incrementAndCheckState(9L);
+        assertFalse(circuit.incrementAndCheckState(1L), "Circuit opened before reaching the threshold");
+    }
+
+    /**
+     * Tests that exceeding the threshold raises an exception.
+     */
+    @Test
+    public void testThresholdCircuitBreakingException() {
+        final ThresholdCircuitBreaker circuit = new ThresholdCircuitBreaker(threshold);
+        circuit.incrementAndCheckState(9L);
+        assertTrue(circuit.incrementAndCheckState(2L), "The circuit was supposed to be open after increment above the threshold");
+    }
+
+    /**
+     * Test that when threshold is zero, the circuit breaker is always open.
+     */
+    @Test
+    public void testThresholdEqualsZero() {
+        final ThresholdCircuitBreaker circuit = new ThresholdCircuitBreaker(zeroThreshold);
+        assertTrue(circuit.incrementAndCheckState(0L), "When the threshold is zero, the circuit is supposed to be always open");
+    }
+
+    /**
+     * Tests that closing a {@code ThresholdCircuitBreaker} resets the internal counter.
+     */
+    @Test
+    public void testClosingThresholdCircuitBreaker() {
+        final ThresholdCircuitBreaker circuit = new ThresholdCircuitBreaker(threshold);
+        circuit.incrementAndCheckState(9L);
+        circuit.close();
+        // now the internal counter is back at zero, not 9 anymore. So it is safe to increment 9 again
+        assertFalse(circuit.incrementAndCheckState(9L), "Internal counter was not reset back to zero");
+    }
+
+    /**
+     * Tests that we can get the threshold value correctly.
+     */
+    @Test
+    public void testGettingThreshold() {
+        final ThresholdCircuitBreaker circuit = new ThresholdCircuitBreaker(threshold);
+        assertEquals(Long.valueOf(threshold), Long.valueOf(circuit.getThreshold()), "Wrong value of threshold");
+    }
+
+}