diff --git a/test/openssl/test_ossl.rb b/test/openssl/test_ossl.rb
index 9f4b39d4f5..2e06203ece 100644
--- a/test/openssl/test_ossl.rb
+++ b/test/openssl/test_ossl.rb
@@ -63,7 +63,7 @@ class OpenSSL::OSSL < OpenSSL::SSLTestCase
     end
     assert_operator(a_b_time, :<, a_c_time * 10, "fixed_length_secure_compare timing test failed")
     assert_operator(a_c_time, :<, a_b_time * 10, "fixed_length_secure_compare timing test failed")
-  end
+  end if ENV["OSSL_TEST_ALL"] == "1"
 
   def test_error_data
     # X509V3_EXT_nconf_nid() called from OpenSSL::X509::ExtensionFactory#create_ext is a function
diff --git a/test/openssl/test_pkey_dh.rb b/test/openssl/test_pkey_dh.rb
index cf56032cb3..c82f642c01 100644
--- a/test/openssl/test_pkey_dh.rb
+++ b/test/openssl/test_pkey_dh.rb
@@ -16,7 +16,7 @@ class OpenSSL::TestPKeyDH < OpenSSL::PKeyTestCase
     # This test is slow
     dh = OpenSSL::PKey::DH.new(NEW_KEYLEN)
     assert_key(dh)
-  end if ENV["OSSL_TEST_ALL"]
+  end if ENV["OSSL_TEST_ALL"] == "1"
 
   def test_new_break
     unless openssl? && OpenSSL.fips_mode
diff --git a/test/openssl/test_pkey_dsa.rb b/test/openssl/test_pkey_dsa.rb
index b882476346..f3324b04af 100644
--- a/test/openssl/test_pkey_dsa.rb
+++ b/test/openssl/test_pkey_dsa.rb
@@ -47,11 +47,11 @@ class OpenSSL::TestPKeyDSA < OpenSSL::PKeyTestCase
     assert_equal 1024, key1024.p.num_bits
     assert_equal 160, key1024.q.num_bits
 
-    key2048 = OpenSSL::PKey::DSA.generate(2048)
-    assert_equal 2048, key2048.p.num_bits
-    assert_equal 256, key2048.q.num_bits
-
     if ENV["OSSL_TEST_ALL"] == "1" # slow
+      key2048 = OpenSSL::PKey::DSA.generate(2048)
+      assert_equal 2048, key2048.p.num_bits
+      assert_equal 256, key2048.q.num_bits
+
       key3072 = OpenSSL::PKey::DSA.generate(3072)
       assert_equal 3072, key3072.p.num_bits
       assert_equal 256, key3072.q.num_bits
diff --git a/test/openssl/test_ssl_session.rb b/test/openssl/test_ssl_session.rb
index f453f58657..37874ca273 100644
--- a/test/openssl/test_ssl_session.rb
+++ b/test/openssl/test_ssl_session.rb
@@ -222,7 +222,7 @@ __EOS__
 
   # Skipping tests that use session_remove_cb by default because it may cause
   # deadlock.
-  TEST_SESSION_REMOVE_CB = ENV["OSSL_TEST_ALL"] == "1"
+  TEST_SESSION_REMOVE_CB = ENV["OSSL_TEST_UNSAFE"] == "1"
 
   def test_ctx_client_session_cb_tls12
     start_server do |port|