Overview

Teaching: 5 min
Exercises: 20 min

Questions

• How does a realistic workflow look for a physics analysis?

Objectives

• Actually add a test on the output of running physics

So at this point, I’m going to be very hands-off, and just explain what you will be doing. Here’s where you should be starting from:

...
...
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 skim:
   needs: build_skim
   runs-on: ubuntu-latest
   container: rootproject/root:6.26.10-conda
   steps:
     - name: checkout repository
       uses: actions/checkout@v4

    - uses: actions/download-artifact@v4
      with:
        name: skim6.26.10

    - name: skim
      run: |
        chmod +x ./skim
        ./skim root://eospublic.cern.ch//eos/root-eos/HiggsTauTauReduced/GluGluToHToTauTau.root skim_ggH.root 19.6 11467.0 0.1

    - uses: actions/upload-artifact@v4
      with:
        name: skim_ggH
        path: skim_ggH.root

 plot:
   needs: skim
   runs-on: ubuntu-latest
   container: rootproject/root:6.26.10-conda
   steps:
     - name: checkout repository
       uses: actions/checkout@v4

    - uses: actions/download-artifact@v4
      with:
        name: skim_ggH

    - name: plot
      run: python histograms.py skim_ggH.root ggH hist_ggH.root

    - uses: actions/upload-artifact@v4
      with:
        name: histograms
        path: hist_ggH.root

Adding a regression test

1. Add a test job, test_ggH that has the right dependencies
   • Note: ./skim needs to be updated to produce a skim_ggH.log (hint: ./skim .... > skim_ggH.log)
   • We also need the hist_ggH.root file produced by the plot job
2. Create a directory called tests/ and make two python files in it named test_cutflow_ggH.py and test_plot_ggH.py that uses PyROOT and python3
   • you might find the following lines (below) helpful to set up the tests
3. Write a few different tests of your choosing that tests (and asserts) something about hist_ggH.root. Some ideas are:
   • check the structure (does ggH_pt_1 exist?)
   • check that the integral of a histogram matches a value you expect
   • check that the bins of a histogram matches the values you expect
4. Update your test_ggH job to execute the regression tests
5. Try causing your CI/CD to fail on the test_ggH job

Done?

Once you’re happy with setting up the regression test, mark your merge request as ready by clicking the Resolve WIP Status button, and then merge it in to main.

Template for test_cutflow_ggH.py

import sys

logfile = open('skim_ggH.log', 'r')
lines = [line.rstrip() for line in logfile]

required_lines = [
   'Number of events: 47696',
   'Cross-section: 19.6',
   'Integrated luminosity: 11467',
   'Global scaling: 0.1',
   'Passes trigger: pass=3402       all=47696      -- eff=7.13 % cumulative eff=7.13 %',
   'nMuon > 0 : pass=3402       all=3402       -- eff=100.00 % cumulative eff=7.13 %',
   'nTau > 0  : pass=3401       all=3402       -- eff=99.97 % cumulative eff=7.13 %',
   'Event has good taus: pass=846        all=3401       -- eff=24.88 % cumulative eff=1.77 %',
   'Event has good muons: pass=813        all=846        -- eff=96.10 % cumulative eff=1.70 %',
   'Valid muon in selected pair: pass=813        all=813        -- eff=100.00 % cumulative eff=1.70 %',
   'Valid tau in selected pair: pass=813        all=813        -- eff=100.00 % cumulative eff=1.70 %',
]

print('\n'.join(lines))
for required_line in required_lines:
    if not required_line in lines:
        print(f'Did not find line in log file. {required_line}')
        sys.exit(1)

Template for test_plot_ggH.py

import sys
import ROOT

f = ROOT.TFile.Open('hist_ggH.root')
keys = [k.GetName() for k in f.GetListOfKeys()]

required_keys = ['ggH_pt_1', 'ggH_pt_2']

print('\n'.join(keys))
for required_key in required_keys:
    if not required_key in keys:
        print(f'Required key not found. {required_key}')
        sys.exit(1)

integral = f.ggH_pt_1.Integral()
if abs(integral - 222.88716647028923) > 0.0001:
    print(f'Integral of ggH_pt_1 is different: {integral}')
    sys.exit(1)

Key Points

• This kind of test is a regression test, as we’re testing assuming the code up to this point was correct.

• This is not a unit test. Unit tests would be testing individual pieces of the Framework code-base, or specific functionality you wrote into your algorithms.