Test ssl_pthread_server

Test ssl_pthread_server with both TLS 1.2 and TLS 1.3.
Test against both OpenSSL and GnuTLS.

In the server, flush more often. Otherwise, when stdout is redirected to a
file, the server gets killed before it writes important information, such as
the logs that we expect in the test cases.

Clean up compile-time requirements in ssl_pthread_server.c: any certificate-based
key exchange is ok, so don't insist on built-in RSA.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/opt-testcases/sample.sh b/tests/opt-testcases/sample.sh
index 82a95b8..4684172 100644
--- a/tests/opt-testcases/sample.sh
+++ b/tests/opt-testcases/sample.sh
@@ -118,3 +118,47 @@
             -c "Description:.*TLS1.3" \
             -S "error" \
             -C "ERROR"
+
+requires_protocol_version tls12
+run_test    "Sample: ssl_pthread_server, openssl client, TLS 1.2" \
+            -P 4433 \
+            "$PROGRAMS_DIR/ssl_pthread_server" \
+            "$O_CLI -tls1_2" \
+            0 \
+            -s "Successful connection using: TLS-" \
+            -c "New, TLSv1.2, Cipher is" \
+            -S "error" \
+            -C "ERROR"
+
+requires_protocol_version tls12
+run_test    "Sample: ssl_pthread_server, gnutls client, TLS 1.2" \
+            -P 4433 \
+            "$PROGRAMS_DIR/ssl_pthread_server" \
+            "$G_CLI --priority=NORMAL:-VERS-TLS-ALL:+VERS-TLS1.2 localhost" \
+            0 \
+            -s "Successful connection using: TLS-" \
+            -c "Description:.*TLS1.2" \
+            -S "error" \
+            -C "ERROR"
+
+requires_protocol_version tls13
+run_test    "Sample: ssl_pthread_server, openssl client, TLS 1.3" \
+            -P 4433 \
+            "$PROGRAMS_DIR/ssl_pthread_server" \
+            "$O_CLI -tls1_3" \
+            0 \
+            -s "Successful connection using: TLS1-3-" \
+            -c "New, TLSv1.3, Cipher is" \
+            -S "error" \
+            -C "ERROR"
+
+requires_protocol_version tls13
+run_test    "Sample: ssl_pthread_server, gnutls client, TLS 1.3" \
+            -P 4433 \
+            "$PROGRAMS_DIR/ssl_pthread_server" \
+            "$G_CLI --priority=NORMAL:-VERS-TLS-ALL:+VERS-TLS1.3 localhost" \
+            0 \
+            -s "Successful connection using: TLS1-3-" \
+            -c "Description:.*TLS1.3" \
+            -S "error" \
+            -C "ERROR"