yaml-cpp trouble parsing mixed array/string nodes

Question

I have the following yaml script that I have tested here: online yaml parser

testcases:
- testcase:
    desc: 'TEST TC1'
    requirement-ref: Doors-10.1.1.0
    given:
      text: 'A UUT, TEST2 and TEST are connected'
      devices:
      - Device:
          Type: UUT
          Status: Connected
      - Device:
          Type: TEST
          Status: Connected
      - Device:
          Type: TEST2
          Status: Connected

- testcase: # next test case...
    desc: 'TEST TC2'

Then I have the following code:

#include <iostream>
#include <unistd.h>
#include <ctime>
#include "yaml-cpp/yaml.h"

using namespace std;

void load_config()
{
    cout << "loading yaml file\n";

    YAML::Node testfile = YAML::LoadFile("BDD-test-case.yaml");
    if (testfile["testcases"])
    {
        cout << "found testfile[\"testcases\"] - size: " << testfile["testcases"].size() << "\n";
        YAML::Node testcases = testfile["testcases"];

        for (int i = 0; i < testcases.size(); i++)
        {
            YAML::Node testcase = testcases[0];
            cout << "testcase " << i << ":\n";
            cout << "\tsize:" << testcase.size() << "\n";
            cout << "\tIsNull:" << testcase.IsNull() << "\n";

            YAML::Node desc = testcase["desc"];
            if (desc)
            {
                std::string desc_str = desc.as<std::string>();
                cout << "desc: " << desc_str.c_str() << "\n";
            }
        }
    }
    cout << "yaml - done\n";
}

int main(int argc, char *argv[])
{
    long double lastTimeMS = time(0)*1000;
    long double CurrTimeMS = time(0)*1000;
    int localPort = 31010;
    int remotePort = 31011;
    int procId = 1;

    load_config();

    cout << "Hello World!" << endl;
    return 0;
}

I get the following output:

loading yaml file
found testfile["testcases"] - size: 2
testcase 0:
        size:1
        IsNull:0
testcase 1:
        size:1
        IsNull:0
yaml - done
Hello World!

I am trying to parse through each testcase and print out the value of "desc" field.

As you can see from the debug I am able to find the top level node testcases. I check its size and it is 2 - which is correct. Then I loop through the testcases and store each as a new node testcase = testcases[i]. So far so good. However now I want to see what is inside each testcase - I should find a tsetcase["desc"]... but I don't see that. Infact testcase seems to be null...

What am I doing wrong here?

code_fodder · Accepted Answer · 2016-09-20 06:48:14Z

2

When you look up:

YAML::Node desc = testcase["desc"];

You're trying to look for the desc key in the following node:

testcase:
  desc: 'TEST TC1'
  requirement-ref: Doors-10.1.1.0
  given:
    text: 'A UUT, TEST2 and TEST are connected'
    devices:
    - Device:
        Type: UUT
        Status: Connected
    - Device:
        Type: TEST
        Status: Connected
    - Device:
        Type: TEST2
        Status: Connected

But this node has a top-level map key testcase. You probably didn't intend this; I think if you simply remove that key, then your doc will look like you're intending.

Update

The fixed YAML (removed the extra level of 'tags' that are not intended):

testcases:
-   desc: 'TEST TC1'
    requirement-ref: Doors-10.1.1.0
    given:
      text: 'A UUT, TEST2 and TEST are connected'
      devices:
      -   Type: UUT
          Status: Connected
      -   Type: TEST
          Status: Connected
      -   Type: TEST2
          Status: Connected

-   desc: 'TEST TC2'

edited Sep 20, 2016 at 6:48

code_fodder

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answered Sep 19, 2016 at 14:21

Jesse Beder

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4 Comments

code_fodder Over a year ago

Thanks for that; I am not quite sure what you mean... To clarify, I want "desc" to be a sub-element of "testcase". So a "testcase" is defined as something that has a description "desc", a requirement reference "requirement-ref" and an object called "given" which will itself contain sub-elements. I looked at the JSON output of what I wrote in YAML and I am fairly sure it is what I want.... but the issue is that "testcase" appears to be null :(

Jesse Beder Over a year ago

The path to "desc" in your document is ["testcases"][0]["testcase"]["desc"]. You're trying to read it as ["testcases"][0]["desc"].

code_fodder Over a year ago

Ahhh....I see. So maybe my yaml is wrong as you say - the node "testcase" seems not required, but then I end up with a line that only has a - dash in it... seems odd. +1 for now, I will test it when I get to work tomorrow and upvote the answer too, thanks! :)

code_fodder Over a year ago

Yes that worked nicely thanks :) ... added an update on your answer to show the fixed yaml code.

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