Detect tests with negative failing realizations

[SAKavli]

Issue
Resolves #my_issue

Approach
Short description of the approach

(Screenshot of new behavior in GUI if applicable)

• PR title captures the intent of the changes, and is fitting for release notes.
• Added appropriate release note label
• Commit history is consistent and clean, in line with the contribution guidelines.
• Make sure unit tests pass locally after every commit (git rebase -i main --exec 'just rapid-tests')

When applicable

• When there are user facing changes: Updated documentation
• New behavior or changes to existing untested code: Ensured that unit tests are added (See Ground Rules).
• Large PR: Prepare changes in small commits for more convenient review
• Bug fix: Add regression test for the bug
• Bug fix: Add backport label to latest release (format: 'backport release-branch-name')

[codspeed-hq]

CodSpeed Performance Report

Merging #11971 will not alter performance

_{Comparing SAKavli:investigate-negative-failing-reals-log (a8c812f) with main (2ad6f44)}

Summary

✅ 22 untouched

[Copilot]

Pull Request Overview

This PR adds detection logic to identify when the number of successful realizations exceeds the number of starting realizations, which would indicate an internal error in the experiment run tracking.

• Adds a check after logging experiment results to detect negative failing realizations
• Triggers a ZeroDivisionError when this impossible condition is detected

[Copilot]

The code intentionally triggers a ZeroDivisionError with 1 / 0 to detect a condition that should be impossible. This is a poor error handling approach. Instead, raise a descriptive exception that explains what went wrong.

Suggested fix:

if len(starting_realizations) - num_successful_realizations < 0:
    raise RuntimeError(
        f"Internal error: Number of successful realizations ({num_successful_realizations}) "
        f"exceeds number of starting realizations ({len(starting_realizations)})"
    )

Suggested change

	1 / 0
	raise RuntimeError(
	f"Internal error: Number of successful realizations ({num_successful_realizations}) "
	f"exceeds number of starting realizations ({len(starting_realizations)})"
	)

[Copilot]

This new detection logic for negative failing realizations lacks test coverage. According to the coding guidelines, all new functional paths or behaviors should be covered with unit tests or integration/UI tests.

The test should:

1. Verify that an exception is raised when num_successful_realizations exceeds len(starting_realizations)
2. Use a descriptive test name following the test_that_ convention, such as test_that_internal_error_is_raised_when_successful_realizations_exceed_starting_realizations

[Copilot]

The error message produced by triggering 1 / 0 will be a generic ZeroDivisionError: division by zero, which is unclear and unhelpful for users or developers trying to understand what went wrong. The error message should clearly explain that this is an internal inconsistency where the number of successful realizations exceeds the number of starting realizations.

Suggested change

	1 / 0
	raise ErtRunError(
	"Internal inconsistency: number of successful realizations "
	"exceeds the number of starting realizations. "
	f"Started: {len(starting_realizations)}, "
	f"Successful: {num_successful_realizations}."
	)