diff --git a/CMakeLists.txt b/CMakeLists.txt
index 568d9f5d..cfdd9531 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1992,76 +1992,6 @@ install(FILES AUTHORS
 # Tests
 #############################################################################
 
-include(CTest)
-
-if(BUILD_TESTING)
-    set(LIBLZMA_TESTS
-        test_bcj_exact_size
-        test_block_header
-        test_check
-        test_filter_flags
-        test_filter_str
-        test_hardware
-        test_index
-        test_index_hash
-        test_lzip_decoder
-        test_memlimit
-        test_stream_flags
-        test_vli
-    )
-
-    # MicroLZMA encoder is needed for both encoder and decoder tests.
-    # If MicroLZMA decoder is not configured but LZMA1 decoder is, then
-    # test_microlzma will fail to compile because this configuration is
-    # not possible in the Autotools build, so the test was not made to
-    # support it since it would have required additional changes.
-    if (MICROLZMA_ENCODER AND (MICROLZMA_DECODER
-            OR NOT "lzma1" IN_LIST DECODERS))
-        list(APPEND LIBLZMA_TESTS test_microlzma)
-    endif()
-
-    foreach(TEST IN LISTS LIBLZMA_TESTS)
-        add_executable("${TEST}" "tests/${TEST}.c")
-
-        target_include_directories("${TEST}" PRIVATE
-            src/common
-            src/liblzma/api
-            src/liblzma
-        )
-
-        target_link_libraries("${TEST}" PRIVATE liblzma)
-
-        # Put the test programs into their own subdirectory so they don't
-        # pollute the top-level dir which might contain xz and xzdec.
-        set_target_properties("${TEST}" PROPERTIES
-            RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/tests_bin"
-        )
-
-        add_test(NAME "${TEST}"
-                 COMMAND "${CMAKE_CURRENT_BINARY_DIR}/tests_bin/${TEST}"
-        )
-
-        # Set srcdir environment variable so that the tests find their
-        # input files from the source tree.
-        #
-        # Set the return code for skipped tests to match Automake convention.
-        set_tests_properties("${TEST}" PROPERTIES
-            ENVIRONMENT "srcdir=${CMAKE_CURRENT_SOURCE_DIR}/tests"
-            SKIP_RETURN_CODE 77
-        )
-    endforeach()
-
-    if(UNIX AND HAVE_DECODERS)
-        file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/test_scripts")
-
-        add_test(NAME test_scripts.sh
-            COMMAND "${CMAKE_CURRENT_SOURCE_DIR}/tests/test_scripts.sh" ".."
-            WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/test_scripts"
-        )
-
-        set_tests_properties(test_scripts.sh PROPERTIES
-            ENVIRONMENT "srcdir=${CMAKE_CURRENT_SOURCE_DIR}/tests"
-            SKIP_RETURN_CODE 77
-        )
-    endif()
-endif()
+# Tests are in a separate file so that it's possible to delete the whole
+# "tests" directory and still have a working build, just without the tests.
+include(tests/tests.cmake OPTIONAL)
diff --git a/tests/Makefile.am b/tests/Makefile.am
index e6516213..d85328dd 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -4,6 +4,7 @@
 EXTRA_DIST = \
 	files \
 	ossfuzz \
+	tests.cmake \
 	tuktest.h \
 	tests.h \
 	test_files.sh \
diff --git a/tests/tests.cmake b/tests/tests.cmake
new file mode 100644
index 00000000..5dd65e42
--- /dev/null
+++ b/tests/tests.cmake
@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: 0BSD
+
+#############################################################################
+#
+# Optional file to be included by the top-level CMakeLists.txt to run tests
+#
+# The CMake rules for the tests are in this separate optional file so
+# that it's trivial to just delete the whole "tests" directory and still
+# get an otherwise normal CMake-based build. This way it's easy to ensure
+# that nothing in the "tests" directory can affect the build process.
+#
+# Author: Lasse Collin
+#
+#############################################################################
+
+include(CTest)
+
+if(BUILD_TESTING)
+    set(LIBLZMA_TESTS
+        test_bcj_exact_size
+        test_block_header
+        test_check
+        test_filter_flags
+        test_filter_str
+        test_hardware
+        test_index
+        test_index_hash
+        test_lzip_decoder
+        test_memlimit
+        test_stream_flags
+        test_vli
+    )
+
+    # MicroLZMA encoder is needed for both encoder and decoder tests.
+    # If MicroLZMA decoder is not configured but LZMA1 decoder is, then
+    # test_microlzma will fail to compile because this configuration is
+    # not possible in the Autotools build, so the test was not made to
+    # support it since it would have required additional changes.
+    if (MICROLZMA_ENCODER AND (MICROLZMA_DECODER
+            OR NOT "lzma1" IN_LIST DECODERS))
+        list(APPEND LIBLZMA_TESTS test_microlzma)
+    endif()
+
+    foreach(TEST IN LISTS LIBLZMA_TESTS)
+        add_executable("${TEST}" "tests/${TEST}.c")
+
+        target_include_directories("${TEST}" PRIVATE
+            src/common
+            src/liblzma/api
+            src/liblzma
+        )
+
+        target_link_libraries("${TEST}" PRIVATE liblzma)
+
+        # Put the test programs into their own subdirectory so they don't
+        # pollute the top-level dir which might contain xz and xzdec.
+        set_target_properties("${TEST}" PROPERTIES
+            RUNTIME_OUTPUT_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/tests_bin"
+        )
+
+        add_test(NAME "${TEST}"
+                 COMMAND "${CMAKE_CURRENT_BINARY_DIR}/tests_bin/${TEST}"
+        )
+
+        # Set srcdir environment variable so that the tests find their
+        # input files from the source tree.
+        #
+        # Set the return code for skipped tests to match Automake convention.
+        set_tests_properties("${TEST}" PROPERTIES
+            ENVIRONMENT "srcdir=${CMAKE_CURRENT_SOURCE_DIR}/tests"
+            SKIP_RETURN_CODE 77
+        )
+    endforeach()
+
+    if(UNIX AND HAVE_DECODERS)
+        file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/test_scripts")
+
+        add_test(NAME test_scripts.sh
+            COMMAND "${CMAKE_CURRENT_SOURCE_DIR}/tests/test_scripts.sh" ".."
+            WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/test_scripts"
+        )
+
+        set_tests_properties(test_scripts.sh PROPERTIES
+            ENVIRONMENT "srcdir=${CMAKE_CURRENT_SOURCE_DIR}/tests"
+            SKIP_RETURN_CODE 77
+        )
+    endif()
+endif()