Test cert alert KEY_USAGE -> UNSUPPORTED_CERT

In terms of line coverage, this was covered, except we never checked the
behaviour was as intended.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 0b8f129..22e6d5e 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -7721,22 +7721,26 @@
 run_test    "keyUsage cli: KeyEncipherment, DHE-RSA: fail" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ke.crt" \
-            "$P_CLI debug_level=1 \
+            "$P_CLI debug_level=3 \
              force_ciphersuite=TLS-DHE-RSA-WITH-AES-128-CBC-SHA" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is TLS-"
+            -C "Ciphersuite is TLS-" \
+            -c "send alert level=2 message=43" \
+            -C "! Usage does not match the keyUsage extension"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 run_test    "keyUsage cli: KeyEncipherment, DHE-RSA: fail, soft" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ke.crt" \
-            "$P_CLI debug_level=1 auth_mode=optional \
+            "$P_CLI debug_level=3 auth_mode=optional \
              force_ciphersuite=TLS-DHE-RSA-WITH-AES-128-CBC-SHA" \
             0 \
             -c "bad certificate (usage extensions)" \
             -C "Processing of the Certificate handshake message failed" \
             -c "Ciphersuite is TLS-" \
+            -C "send alert level=2 message=43" \
             -c "! Usage does not match the keyUsage extension"
 
 run_test    "keyUsage cli: DigitalSignature, DHE-RSA: OK" \
@@ -7752,22 +7756,26 @@
 run_test    "keyUsage cli: DigitalSignature, RSA: fail" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ds.crt" \
-            "$P_CLI debug_level=1 \
+            "$P_CLI debug_level=3 \
              force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
             1 \
             -c "bad certificate (usage extensions)" \
             -c "Processing of the Certificate handshake message failed" \
-            -C "Ciphersuite is TLS-"
+            -C "Ciphersuite is TLS-" \
+            -c "send alert level=2 message=43" \
+            -C "! Usage does not match the keyUsage extension"
+            # MBEDTLS_X509_BADCERT_KEY_USAGE -> MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT
 
 run_test    "keyUsage cli: DigitalSignature, RSA: fail, soft" \
             "$O_SRV -tls1_2 -key $DATA_FILES_PATH/server2.key \
              -cert $DATA_FILES_PATH/server2.ku-ds.crt" \
-            "$P_CLI debug_level=1 auth_mode=optional \
+            "$P_CLI debug_level=3 auth_mode=optional \
              force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
             0 \
             -c "bad certificate (usage extensions)" \
             -C "Processing of the Certificate handshake message failed" \
             -c "Ciphersuite is TLS-" \
+            -C "send alert level=2 message=43" \
             -c "! Usage does not match the keyUsage extension"
 
 requires_openssl_tls1_3_with_compatible_ephemeral