diff --git a/web/src/test/java/org/springframework/security/web/authentication/ott/GenerateOneTimeTokenFilterTests.java b/web/src/test/java/org/springframework/security/web/authentication/ott/GenerateOneTimeTokenFilterTests.java
new file mode 100644
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+++ b/web/src/test/java/org/springframework/security/web/authentication/ott/GenerateOneTimeTokenFilterTests.java
@@ -0,0 +1,115 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed 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
+ *
+ *      https://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.springframework.security.web.authentication.ott;
+
+import java.io.IOException;
+import java.time.Instant;
+
+import jakarta.servlet.ServletException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentMatchers;
+
+import org.springframework.mock.web.MockFilterChain;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.security.authentication.ott.DefaultOneTimeToken;
+import org.springframework.security.authentication.ott.GenerateOneTimeTokenRequest;
+import org.springframework.security.authentication.ott.OneTimeTokenService;
+import org.springframework.security.web.server.authentication.ott.GenerateOneTimeTokenWebFilter;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link GenerateOneTimeTokenWebFilter}
+ *
+ * @author Max Batischev
+ */
+public class GenerateOneTimeTokenFilterTests {
+
+	private final OneTimeTokenService oneTimeTokenService = mock(OneTimeTokenService.class);
+
+	private final RedirectOneTimeTokenGenerationSuccessHandler successHandler = new RedirectOneTimeTokenGenerationSuccessHandler(
+			"/login/ott");
+
+	private static final String TOKEN = "token";
+
+	private static final String USERNAME = "user";
+
+	private final MockHttpServletRequest request = new MockHttpServletRequest();
+
+	private final MockHttpServletResponse response = new MockHttpServletResponse();
+
+	private final MockFilterChain filterChain = new MockFilterChain();
+
+	@BeforeEach
+	void setup() {
+		this.request.setMethod("POST");
+		this.request.setServletPath("/ott/generate");
+	}
+
+	@Test
+	void filterWhenUsernameFormParamIsPresentThenSuccess() throws ServletException, IOException {
+		given(this.oneTimeTokenService.generate(ArgumentMatchers.any(GenerateOneTimeTokenRequest.class)))
+			.willReturn(new DefaultOneTimeToken(TOKEN, USERNAME, Instant.now()));
+		this.request.setParameter("username", USERNAME);
+
+		GenerateOneTimeTokenFilter filter = new GenerateOneTimeTokenFilter(this.oneTimeTokenService,
+				this.successHandler);
+
+		filter.doFilter(this.request, this.response, this.filterChain);
+
+		verify(this.oneTimeTokenService).generate(ArgumentMatchers.any(GenerateOneTimeTokenRequest.class));
+		assertThat(this.response.getRedirectedUrl()).isEqualTo("/login/ott");
+	}
+
+	@Test
+	void filterWhenUsernameFormParamIsEmptyThenNull() throws ServletException, IOException {
+		given(this.oneTimeTokenService.generate(ArgumentMatchers.any(GenerateOneTimeTokenRequest.class)))
+			.willReturn((new DefaultOneTimeToken(TOKEN, USERNAME, Instant.now())));
+		GenerateOneTimeTokenFilter filter = new GenerateOneTimeTokenFilter(this.oneTimeTokenService,
+				this.successHandler);
+
+		filter.doFilter(this.request, this.response, this.filterChain);
+
+		verify(this.oneTimeTokenService, never()).generate(ArgumentMatchers.any(GenerateOneTimeTokenRequest.class));
+	}
+
+	@Test
+	public void constructorWhenOneTimeTokenServiceNullThenIllegalArgumentException() {
+		// @formatter:off
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> new GenerateOneTimeTokenFilter(null, this.successHandler));
+		// @formatter:on
+	}
+
+	@Test
+	public void setWhenRequestMatcherNullThenIllegalArgumentException() {
+		GenerateOneTimeTokenFilter filter = new GenerateOneTimeTokenFilter(this.oneTimeTokenService,
+				this.successHandler);
+		// @formatter:off
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> filter.setRequestMatcher(null));
+		// @formatter:on
+	}
+
+}