[test] add expect tests for coap and coaps (#5172)

Also adds command coaps set to make it consistent with coap set.
diff --git a/.github/workflows/simulation.yml b/.github/workflows/simulation.yml
index 44a3be0..1c95ca3 100644
--- a/.github/workflows/simulation.yml
+++ b/.github/workflows/simulation.yml
@@ -172,6 +172,9 @@
 
   expects:
     runs-on: ubuntu-18.04
+    env:
+      CFLAGS: -DCLI_COAP_SECURE_USE_COAP_DEFAULT_HANDLER=1
+      CXXFLAGS: -DCLI_COAP_SECURE_USE_COAP_DEFAULT_HANDLER=1
     steps:
     - uses: actions/checkout@v2
     - name: Bootstrap
diff --git a/src/cli/README_COAPS.md b/src/cli/README_COAPS.md
index 34c9b23..2d31fee 100644
--- a/src/cli/README_COAPS.md
+++ b/src/cli/README_COAPS.md
@@ -100,6 +100,7 @@
 - [psk](#psk-psk-pskid)
 - [put](#put-uri-path-type-payload)
 - [resource](#resource-uri-path)
+- [set](#set-new-content)
 - [start](#start)
 - [stop](#stop)
 - [x509](#x509)
@@ -119,6 +120,7 @@
 psk
 put
 resource
+set
 start
 stop
 x509
@@ -214,6 +216,15 @@
 Done
 ```
 
+### set \[new-content\]
+
+Sets the content sent by the test resource.
+
+```bash
+> coaps set Testing123
+Done
+```
+
 ### start
 
 Starts the application coaps service.
diff --git a/src/cli/cli_coap.cpp b/src/cli/cli_coap.cpp
index 635067c..89a9f04 100644
--- a/src/cli/cli_coap.cpp
+++ b/src/cli/cli_coap.cpp
@@ -83,7 +83,8 @@
     memset(&mRequestUri, 0, sizeof(mRequestUri));
 #endif
     memset(&mUriPath, 0, sizeof(mUriPath));
-    strncpy(mResourceContent, "0", sizeof(mResourceContent) - 1);
+    strncpy(mResourceContent, "0", sizeof(mResourceContent));
+    mResourceContent[sizeof(mResourceContent) - 1] = '\0';
 }
 
 #if OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE
@@ -214,8 +215,9 @@
 
     if (aArgsLength > 1)
     {
-        VerifyOrExit(strlen(aArgs[1]) < (kMaxBufferSize - 1), error = OT_ERROR_INVALID_ARGS);
-        strncpy(mResourceContent, aArgs[1], sizeof(mResourceContent) - 1);
+        VerifyOrExit(strlen(aArgs[1]) < sizeof(mResourceContent), error = OT_ERROR_INVALID_ARGS);
+        strncpy(mResourceContent, aArgs[1], sizeof(mResourceContent));
+        mResourceContent[sizeof(mResourceContent) - 1] = '\0';
 
 #if OPENTHREAD_CONFIG_COAP_OBSERVE_API_ENABLE
         if (mSubscriberTokenLength > 0)
diff --git a/src/cli/cli_coap_secure.cpp b/src/cli/cli_coap_secure.cpp
index 1fe87c4..0787a0d 100644
--- a/src/cli/cli_coap_secure.cpp
+++ b/src/cli/cli_coap_secure.cpp
@@ -51,7 +51,8 @@
     {"delete", &CoapSecure::ProcessRequest}, {"disconnect", &CoapSecure::ProcessDisconnect},
     {"get", &CoapSecure::ProcessRequest},    {"post", &CoapSecure::ProcessRequest},
     {"put", &CoapSecure::ProcessRequest},    {"resource", &CoapSecure::ProcessResource},
-    {"start", &CoapSecure::ProcessStart},    {"stop", &CoapSecure::ProcessStop},
+    {"set", &CoapSecure::ProcessSet},        {"start", &CoapSecure::ProcessStart},
+    {"stop", &CoapSecure::ProcessStop},
 #ifdef MBEDTLS_KEY_EXCHANGE_PSK_ENABLED
     {"psk", &CoapSecure::ProcessPsk},
 #endif
@@ -70,6 +71,8 @@
     memset(&mResource, 0, sizeof(mResource));
     memset(&mPsk, 0, sizeof(mPsk));
     memset(&mPskId, 0, sizeof(mPskId));
+    strncpy(mResourceContent, "0", sizeof(mResourceContent));
+    mResourceContent[sizeof(mResourceContent) - 1] = '\0';
 }
 
 void CoapSecure::PrintPayload(otMessage *aMessage) const
@@ -135,6 +138,25 @@
     return error;
 }
 
+otError CoapSecure::ProcessSet(uint8_t aArgsLength, char *aArgs[])
+{
+    otError error = OT_ERROR_NONE;
+
+    if (aArgsLength > 1)
+    {
+        VerifyOrExit(strlen(aArgs[1]) < sizeof(mResourceContent), error = OT_ERROR_INVALID_ARGS);
+        strncpy(mResourceContent, aArgs[1], sizeof(mResourceContent));
+        mResourceContent[sizeof(mResourceContent) - 1] = '\0';
+    }
+    else
+    {
+        mInterpreter.mServer->OutputFormat("%s\r\n", mResourceContent);
+    }
+
+exit:
+    return error;
+}
+
 otError CoapSecure::ProcessStart(uint8_t aArgsLength, char *aArgs[])
 {
     otError error;
@@ -447,10 +469,9 @@
 
 void CoapSecure::HandleRequest(otMessage *aMessage, const otMessageInfo *aMessageInfo)
 {
-    otError    error             = OT_ERROR_NONE;
-    otMessage *responseMessage   = nullptr;
-    otCoapCode responseCode      = OT_COAP_CODE_EMPTY;
-    char       responseContent[] = "helloWorld";
+    otError    error           = OT_ERROR_NONE;
+    otMessage *responseMessage = nullptr;
+    otCoapCode responseCode    = OT_COAP_CODE_EMPTY;
 
     mInterpreter.mServer->OutputFormat("coaps request from ");
     mInterpreter.OutputIp6Address(aMessageInfo->mPeerAddr);
@@ -506,7 +527,8 @@
 
         if (otCoapMessageGetCode(aMessage) == OT_COAP_CODE_GET)
         {
-            SuccessOrExit(error = otMessageAppend(responseMessage, &responseContent, sizeof(responseContent)));
+            SuccessOrExit(error = otMessageAppend(responseMessage, &mResourceContent,
+                                                  static_cast<uint16_t>(strlen(mResourceContent))));
         }
 
         SuccessOrExit(error = otCoapSecureSendResponse(mInterpreter.mInstance, responseMessage, aMessageInfo));
diff --git a/src/cli/cli_coap_secure.hpp b/src/cli/cli_coap_secure.hpp
index 660c79f..e81e24f 100644
--- a/src/cli/cli_coap_secure.hpp
+++ b/src/cli/cli_coap_secure.hpp
@@ -97,6 +97,7 @@
     otError ProcessPsk(uint8_t aArgsLength, char *aArgs[]);
     otError ProcessRequest(uint8_t aArgsLength, char *aArgs[]);
     otError ProcessResource(uint8_t aArgsLength, char *aArgs[]);
+    otError ProcessSet(uint8_t aArgsLength, char *aArgs[]);
     otError ProcessStart(uint8_t aArgsLength, char *aArgs[]);
     otError ProcessStop(uint8_t aArgsLength, char *aArgs[]);
     otError ProcessX509(uint8_t aArgsLength, char *aArgs[]);
@@ -122,6 +123,7 @@
 
     otCoapResource mResource;
     char           mUriPath[kMaxUriLength];
+    char           mResourceContent[kMaxBufferSize];
 
     bool    mShutdownFlag;
     bool    mUseCertificate;
diff --git a/tests/scripts/expect/cli-coap.exp b/tests/scripts/expect/cli-coap.exp
new file mode 100755
index 0000000..cbd4ffa
--- /dev/null
+++ b/tests/scripts/expect/cli-coap.exp
@@ -0,0 +1,114 @@
+#!/usr/bin/expect -f
+#
+#  Copyright (c) 2020, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+
+source "tests/scripts/expect/_multinode.exp"
+
+set timeout 3
+setup_nodes
+
+set spawn_id $spawn_1
+send "coap start\n"
+expect "Done"
+send "coap resource test/resource\n"
+expect "Done"
+send "coap set Testing123\n"
+expect "Done"
+send "ipaddr mleid\n"
+expect "ipaddr mleid"
+expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
+set addr_1 $expect_out(1,string)
+expect "Done"
+
+set spawn_id $spawn_2
+send "coap start\n"
+expect "Done"
+send "coap parameters request 3000 4 3 5\n"
+expect "Transmission parameters for request:"
+expect "ACK_TIMEOUT=3000 ms, ACK_RANDOM_FACTOR=4/3, MAX_RETRANSMIT=5"
+expect "Done"
+send "coap parameters response 2500 4 3 3\n"
+expect "Transmission parameters for response:"
+expect "ACK_TIMEOUT=2500 ms, ACK_RANDOM_FACTOR=4/3, MAX_RETRANSMIT=3"
+expect "Done"
+send "coap get $addr_1 test/resource\n"
+expect "Done"
+expect "coap response from $addr_1 with payload: 54657374696e67313233" # ASCII of "Testing123"
+send "coap post $addr_1 test/resource con Testing123\n"
+expect "Done"
+expect "coap response from $addr_1"
+send "coap put $addr_1 test/resource con Testing123\n"
+expect "Done"
+expect "coap response from $addr_1"
+send "coap delete $addr_1 test/resource con\n"
+expect "Done"
+expect "coap response from $addr_1"
+send "coap post $addr_1 test/resource none Testing123\n"
+expect "Done"
+send "ipaddr mleid\n"
+expect "ipaddr mleid"
+expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
+set addr_2 $expect_out(1,string)
+expect "Done"
+
+set spawn_id $spawn_1
+expect "coap request from $addr_2 GET"
+expect "coap response sent"
+expect "coap request from $addr_2 POST with payload: 54657374696e67313233"
+expect "coap response sent"
+expect "coap request from $addr_2 PUT with payload: 54657374696e67313233"
+expect "coap response sent"
+expect "coap request from $addr_2 DELETE"
+expect "coap response sent"
+expect "coap request from $addr_2 POST with payload: 54657374696e67313233"
+send "coap resource\n"
+expect "test/resource"
+expect "Done"
+send "coap set\n"
+expect "Testing123"
+expect "Done"
+send "coap parameters request default\n"
+expect "Transmission parameters for request:"
+expect "default"
+expect "Done"
+send "coap parameters response default\n"
+expect "Transmission parameters for response:"
+expect "default"
+expect "Done"
+send "coap help\n"
+expect "Done"
+send "coap parameters something_invalid\n"
+expect "Error 7: InvalidArgs"
+send "coap get\n"
+expect "Error 7: InvalidArgs"
+send "coap get $addr_2\n"
+expect "Error 7: InvalidArgs"
+send "coap\n"
+expect "Error 7: InvalidArgs"
+
+dispose_nodes
diff --git a/tests/scripts/expect/cli-coaps.exp b/tests/scripts/expect/cli-coaps.exp
new file mode 100755
index 0000000..5c190a2
--- /dev/null
+++ b/tests/scripts/expect/cli-coaps.exp
@@ -0,0 +1,116 @@
+#!/usr/bin/expect -f
+#
+#  Copyright (c) 2020, The OpenThread Authors.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+#  2. Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#  3. Neither the name of the copyright holder nor the
+#     names of its contributors may be used to endorse or promote products
+#     derived from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+#  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+#  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+#  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+#  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+#  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+#  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+#  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+#  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGE.
+#
+
+source "tests/scripts/expect/_multinode.exp"
+
+set timeout 3
+setup_nodes
+
+set spawn_id $spawn_1
+send "coaps x509\n"
+expect "Done"
+send "coaps start\n"
+expect "Done"
+send "coaps resource test/resource\n"
+expect "Done"
+send "coaps set Testing123\n"
+expect "Done"
+send "ipaddr mleid\n"
+expect "ipaddr mleid"
+expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
+set addr_1 $expect_out(1,string)
+expect "Done"
+
+set spawn_id $spawn_2
+send "coaps x509\n"
+expect "Done"
+send "coaps start\n"
+expect "Done"
+send "coaps connect $addr_1 5684\n"
+expect "Done"
+expect "coaps connected"
+send "coaps get $addr_1 test/resource\n"
+expect "Done"
+expect "coaps response from $addr_1 with payload: 54657374696e67313233" # ASCII of "Testing123"
+send "coaps post $addr_1 test/resource con Testing123\n"
+expect "Done"
+expect "coaps response from $addr_1"
+send "coaps put $addr_1 test/resource con Testing123\n"
+expect "Done"
+expect "coaps response from $addr_1"
+send "coaps delete $addr_1 test/resource con\n"
+expect "Done"
+expect "coaps response from $addr_1"
+send "coaps post $addr_1 test/resource none Testing123\n"
+expect "Done"
+send "coaps get $addr_1 default\n"
+expect "Done"
+expect "coaps response from $addr_1"
+send "ipaddr mleid\n"
+expect "ipaddr mleid"
+expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
+set addr_2 $expect_out(1,string)
+expect "Done"
+
+set spawn_id $spawn_1
+expect "coaps request from $addr_2 GET"
+expect "coaps response sent"
+expect "coaps request from $addr_2 POST with payload: 54657374696e67313233"
+expect "coaps response sent"
+expect "coaps request from $addr_2 PUT with payload: 54657374696e67313233"
+expect "coaps response sent"
+expect "coaps request from $addr_2 DELETE"
+expect "coaps response sent"
+expect "coaps request from $addr_2 POST with payload: 54657374696e67313233"
+send "coaps resource\n"
+expect "test/resource"
+expect "Done"
+send "coaps set\n"
+expect "Testing123"
+expect "Done"
+send "coaps help\n"
+expect "Done"
+send "coaps get\n"
+expect "Error 7: InvalidArgs"
+send "coaps\n"
+expect "Error 7: InvalidArgs"
+send "coaps start false\n"
+expect "Error 24: Already"
+send "coaps start something_invalid\n"
+expect "Error 7: InvalidArgs"
+
+set spawn_id $spawn_2
+send "coaps stop\n"
+expect "Done"
+
+set spawn_id $spawn_1
+send "coaps stop\n"
+expect "Done"
+
+dispose_nodes
diff --git a/tests/scripts/expect/cli-ping.exp b/tests/scripts/expect/cli-ping.exp
index 53271d2..ce5378f 100755
--- a/tests/scripts/expect/cli-ping.exp
+++ b/tests/scripts/expect/cli-ping.exp
@@ -53,7 +53,8 @@
 setup_nodes
 
 set spawn_id $spawn_2
-send "ipaddr\n"
+send "ipaddr mleid\n"
+expect "ipaddr mleid"
 expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
 set addr $expect_out(1,string)
 expect "Done"