TeCo is a deep learning model using code semantics to automatically complete the next statement in a test method. Completing tests requires reasoning about the execution of the code under test, which is hard to do with only syntax-level data that existing code completion models use. To solve this problem, we leverage the fact that tests are readily executable. TeCo extracts and uses execution-guided code semantics as inputs for the ML model, and performs reranking via test execution to improve the outputs. On a large dataset with 131K tests from 1270 open-source Java projects, TeCo outperforms the state-of-the-art by 29% in terms of test completion accuracy.

TeCo is presented in the following ICSE 2023 paper:

Title: Learning Deep Semantics for Test Completion

Authors: Pengyu Nie, Rahul Banerjee, Junyi Jessy Li, Raymond Mooney, Milos Gligoric

• Test Completion Corpus
• Pre-requisites
• Installation
• Usage
• Citation

Our test completion corpus contains several artifacts that are useful at different stages of data collection and model training/evaluation. Some large artifacts need to be downloaded separately from UTBox, and for those we provide download links and instructions to unpack the downloaded files to this repository.

• The list of repositories used in our study.
• In this repository: _work/repos/filtered/
• Contents:
  • repos.json is the list of repositories with metadata.
  • licenses.tgz contains the licenses of these repositories.

• The files of the repositories used in our study, archived in case some repositories are removed or renamed. To reproduce the full data collection + model training/evaluation workflow, you need to download all repositories (large size - 41GB). To reproduce only the model training/evaluation part, you need to download the repositories in the evaluation set (2GB).
• Download link for all repositories: https://utexas.box.com/s/n2gjzd4toy5j4t0sv4ztnngezxrx3rhc
  • Unzip the files (multi-volume zip files) with the following commands: zip -s 0 downloads.zip --out downloads-single.zip && unzip downloads-single.zip && rm downloads-single.zip, then move the extracted downloads folder to this repository at _work/downloads.
• Download link for repositories in the evaluation set: https://utexas.box.com/s/edmidy4h1plpmoeg5ew1bru3qg6zp8hi
  • Unzip the downloaded file with tar xzf downloads.tgz, then move the extracted downloads folder to this repository at _work/downloads.
• Contents:
  • each repository is stored in a separate folder, with the folder name being the {user_name}_{repo_name} (e.g., apache_fluo corresponds to github.com/apache/fluo).

• The processed test completion corpus, ready for use by model training/evaluation (3GB).
• Download link: https://utexas.box.com/s/os5y2iuozindk9z9dcvjahosv427qcnw
  • Unzip the downloaded file with tar xzf data.tgz, then move the extracted data folder to this repository at _work/data.
• Contents:
  • the corpus is stored as multiple jsonl files; each file contains one data field for all examples, with each line for one example (e.g., focalm.jsonl contains the methods under test).
  • config.json contains the configuration for data filtering.
  • filter_counter.json contains the number of repositories/tests/statements that are filtered out.

The following software/hardware are required to run TeCo. GPU is required for training and evaluating the model, but not required if you only use the data collection and processing scripts.

• Linux operating system
• Miniconda or Anaconda
• JDK 8 and Maven 3.8 (recommended to install via sdkman)
• Nvidia GPU with at least 8GB memory, and appropriate driver installed

Run ./check-prereq.sh to check if you have these pre-requisites ready.

Debugging tips: you should have these commands available in PATH: conda, java, mvn, nvidia-smi (if you want to use GPU), nvcc (if you want to use system-installed cuda instead of letting conda install it).

Ensure that you met the pre-requisites before proceeding.

Then, you can install a conda environment for TeCo by running the following script, which includes GPU support if GPU is available:

./prepare-env.sh

After this script finishes, you can activate the conda environment by running:

conda activate teco

If this step is successful you should see a (teco) prefix in the command line prompt. You may need to reactivate this conda environment every time you open a new terminal.

If you need to rerun the installation script, make sure the existing conda environment is deactivated by conda deactivate.

You can run the following commands to quickly check if the installation is successful:

# try if data collection is working
inv data.collect-raw-data --debug

# try if model training is working (requires first downloading the processed corpus)
inv data.eval-setup --debug
inv exp.train-codet5 --setup CSNm-Debug --overwrite --suffix teco-norr --args "--model.inputs=[fields_notset,last_called_method,types_local,types_absent,similar_stmt_1_0,setup_teardown,focalm,sign,prev_stmts] --model.output=stmt --seed_everything=4197"

TL;DR:

• If you have an older GPU (e.g., GTX 1080 Ti) and encounter CUDA-related errors, try ./prepare-env.sh 10.2.
• If you want to use the system-wide installed CUDA (must be 10.2/11.3/11.6) together with cuDNN and NCCL, do ./prepare-env.sh system.

TeCo uses PyTorch 1.12.1, which requires CUDA with version 10.2/11.3/11.6, together with cuDNN and NCCL libraries. Our installation script detects whether GPU is available by checking the output of nvidia-smi. If GPU is not available, this script will install PyTorch in CPU-only mode, which is usually not suitable for training and evaluating the ML models (unless you know what you're doing), but enables the data collection and processing part of the TeCo to run. If GPU is available, this script will install CUDA 11.6, cuDNN, and NCCL in the conda environment. The installed CUDA is only usable when the conda environment is activated.

You can change the CUDA version installed by adding an option to the installation script: ./prepare-env.sh cuda_version, where cuda_version can be cpu, system, 10.2, 11.3, 11.6. Use "cpu" if you want to install PyTorch in CPU-only mode even if GPU is available. Use "system" if you have already performed a system-wide installation of CUDA (must be one of 10.2/11.3/11.6), together with cuDNN and NCCL, and would like to use it instead of installing another CUDA. The default option "11.6" is usually fine especially if you're using a recent GPU, but if you're using an older GPU (e.g., GTX 1080 Ti) and encounter CUDA-related errors, you may want to try "10.2" instead.

This section includes the entire workflow of TeCo's experiments, from data collection and processing to model training and evaluation. Unless otherwise specified, all commands should be run in the project directory and with the teco conda environment activated.

If you're only interested in the model training/evaluation part, download the part of our test completion corpus for that (the processed corpus + the repositories in the evaluation set), then jump to Model training and evaluation.

These steps are for collecting the data for test completion, as well as extracting the code semantics. To simplify debugging, you can add --debug to each command to run them on a small subset of the corpus (but debugging each step requires running the previous step on the full corpus).

Inputs: nothing in addition to the current repo, but in case some subject repositories have been removed from GitHub, you may download our archived repositories files (see Corpus > repositories files).

Outputs: processed corpus at _work/data.

Workflow:

• Collecting code elements
• Extracting syntax-level data
• Extracting code semantics

This step extracts the raw code elements sets from the repositories, i.e., the collection phase in our paper. (time: ~6h)

inv data.collect-raw-data

The extracted code elements will be stored at _work/raw-data.

This step processes the raw code elements sets to extract the syntax-level data (i.e., method under test, test method signature, test method statements). It also performs data filtering based on the criteria described in our paper's Section V. (time: ~1.5h)

inv data.process

The process corpus will be stored at _work/data.

This step extracts the code semantics from the raw code elements sets (i.e., local var types, absent types, unset fields, setup teardown, last called method, similar statement). (time: ~20h)

inv data.extend-data-all

The additional code semantics data will be amended to _work/data.

These steps are for training and evaluating TeCo model after data is collected.

Inputs:

• the processed corpus at _work/data (prepared from Data collection and processing or downloaded from Corpus > processed corpus).
• the subject repositories needed during computing runtime metrics will be automatically cloned from GitHub, but in case some subject repositories have been removed from GitHub, you may download our archived repositories files (see Corpus > repositories files).

Outputs:

• trained model at _work/exp/CSNm/train/CodeT5-teco-norr.
• evaluation results at _work/exp/CSNm/eval-{any,runnable-any,assert,runnable-assert}-stmt/test/SingleEvaluator-teco/bs10-last

Workflow:

• Splitting corpus
• Training model OR Downloading model
• Evaluating model
• Computing compilable/runnable status
• Reranking via execution

inv data.eval-setup

As training and running ML models can be time-consuming, we provide a small version of the corpus after splitting for debugging purposes, CSNm-Debug, with 800/25/25 tests in train/val/eval sets. To obtain this debug version, run:

inv data.eval-setup --debug

The generated sets will be stored in _work/setup/CSNm-Debug. To use it in the following commands of training and evaluating the model, replace --setup CSNm with --setup CSNm-Debug.

The training hyper-parameters are specified in configs/CodeT5.yaml. The default hyper-parameters are suitable for training the model on our machine with 4 GTX 1080Ti GPUs. You may want to change batch_size and gradient_accumulation_steps to fit your GPU configurations.

To train the model: (time: ~20h on our machine with 4 GTX 1080Ti GPUs)

inv exp.train-codet5 --setup CSNm --overwrite --suffix teco-norr --args "--model.inputs=[fields_notset,last_called_method,types_local,types_absent,similar_stmt_1_0,setup_teardown,focalm,sign,prev_stmts] --model.output=stmt --seed_everything=4197"

The trained model will be stored in _work/exp/CSNm/train/CodeT5-teco-norr. Note that the model at this point is the variant of TeCo without reranking (i.e., TeCo-noRr in the paper). You still need to complete a few more steps below to obtain the full TeCo model.

Alternative to training the model yourself, you can download the version of the model we trained from 🤗 hub:

inv exp.pull-model

The pulled model will also be stored in _work/exp/CSNm/train/CodeT5-teco-norr.

To evaluate the trained model on the eval set, run:

inv exp.eval-single --setup CSNm --overwrite --suffix teco-norr --trained CodeT5-teco-norr --decoding bs10 --eval-set eval-any-stmt/test --args "--seed_everything=4197"

The results will be stored in _work/exp/CSNm/eval-any-stmt/test/SingleEvaluator-teco-norr/bs10-last. The metrics_summary.json contains the automated metrics, and the preds.jsonl contains the raw predictions.

Then, compute the metrics on the runnable subset and oracle subset:

inv exp.gen-subset-preds --setup CSNm --model SingleEvaluator-teco-norr --from-set eval-any-stmt/test --to-set eval-runnable-any-stmt/test
inv exp.gen-subset-preds --setup CSNm --model SingleEvaluator-teco-norr --from-set eval-any-stmt/test --to-set eval-assert-stmt/test

The results will be stored in _work/exp/CSNm/eval-runnable-any-stmt/test/SingleEvaluator-teco-norr/bs10-last and _work/exp/CSNm/eval-assert-stmt/test/SingleEvaluator-teco-norr/bs10-last, correspondingly.

The next step is to check if the predicted statements are compilable/runnable on the runnable subset. First, we need to compile the repositories that will be used in the evaluation:

SEUTIL_SHOW_FULL_OUTPUT=1 inv exp.compute-runtime-metrics --setup CSNm --compile-only --models SingleEvaluator-teco-norr

If any compilation error occurs, it means the runtime environment (e.g., JDK 8 and Maven) is not properly set up. Please check the error messages and fix them. The compilation of repositories only need to be done once and can be used for evaluating the compilable/runnable status of any number of models.

Then, compute the compilable/runnable status of the TeCo-noRr model: (time: ~12h)

inv exp.compute-runtime-metrics --setup CSNm --no-compile --models SingleEvaluator-teco-norr --mode="first-runnable" --pool-size=32 --batch-size=200

The results will be amended to _work/exp/CSNm/eval-runnable-any-stmt/test/SingleEvaluator-teco-norr/bs10-last.

Finally, we can compute the metrics (with %compile/%run) on the runnable-oracle subset:

inv exp.gen-subset-preds --setup CSNm --model SingleEvaluator-teco-norr --from-set eval-runnable-any-stmt/test --to-set eval-runnable-assert-stmt/test

The last step is to perform reranking based on the compilable/runnable status:

inv exp.rerank-runnable --setup CSNm --src SingleEvaluator-teco-norr --tgt SingleEvaluator-teco

This will generate the results of the full TeCo model on the evaluation set and its three subsets, located at the following places. eval set: _work/exp/CSNm/eval-any-stmt/test/SingleEvaluator-teco/bs10-last runnable subset: _work/exp/CSNm/eval-runnable-any-stmt/test/SingleEvaluator-teco/bs10-last oracle subset: _work/exp/CSNm/eval-assert-stmt/test/SingleEvaluator-teco/bs10-last runnable-oracle subset: _work/exp/CSNm/eval-runnable-assert-stmt/test/SingleEvaluator-teco/bs10-last

If you have used Teco in a research project, please cite the research paper in any related publication:

@inproceedings{NieETAL22Teco,
  title =        {Learning Deep Semantics for Test Completion},
  author =       {Pengyu Nie and Rahul Banerjee and Junyi Jessy Li and Raymond J. Mooney and Milos Gligoric},
  booktitle =    {International Conference on Software Engineering},
  year =         {2023},
}