[devin-ai-integration]

Summary

Closes a code scan coverage gap: nothing in tests/ exercised StepInfo.save_step_info / ExpResult.get_step_info, so a regression in the screenshot/goal-object offload or in DataclassJSONEncoder would silently corrupt saved episodes.

New tests/experiments/test_loop.py uses tmp_path and no browser/env, asserting:

• screenshots are written as PNGs, stripped from the pickle, and restored onto obs in memory after save
• goal_object is offloaded to goal_object.pkl.gz, replaced by the None placeholder, and re-hydrated by get_step_info
• the goal object is written only once (a later step's differing goal does not overwrite it — current documented behavior)
• save_screenshot=False, save_som=False leaves no PNGs and load tolerates the missing files
• save_json=True produces steps_info.json, with DataclassJSONEncoder converting numpy scalars/arrays and nested dataclasses

Devin-Org: engineering

Link to Devin session: https://app.devin.ai/sessions/2a00f008474244b191b08214cae95b30
Open in Devin Desktop: https://app.devin.ai/desktop/session/2a00f008474244b191b08214cae95b30?variant=devin

[devin-ai-integration]

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