SPOT: Testing Stream Processing Programs with Symbolic Execution and Stream Synthesizing

Round 1

Reviewer 1 Report

This paper proposed a solution called SPOT that efficiently generates test data (i.e., stream) of a program defined as DAG on Apache Flink, a representative DSP system. In particular, an attempt to tackle the challenges of considering the temporal characteristics of stream data and major operators of DSP programs is a very important contribution. In addition, the research background and motivation are clear.

However, some minor revisions below are expected to improve the reader's understanding.
- The abbreviations are well organized at the end of the paper, but please specify the full form where the abbreviation is used first in the body. In particular, in the abstract and introduction. (e.g., JPF, JDU, PC, SMT, etc.)
- Section 3 is very short.
- Although this paper targets a distributed stream processing system, only a single machine is used in the experiment. Do you also consider out-of-order stream data generated by the distributed processing system?
- In Section 2.1, include each of the motivating examples as text in the body (not a figure).
- On Line 207, … concentration is less than 31 … -> … concentration is greater than 31 …
- There is a parenthesis error on lines 214-215.
- Check for a link error on line 239.
- On Line 270, off-the-shell -> off-the-shelf
- In Algorithm 2, “>>” is Tex error.
- The programs in Figure 7 as text, not pictures.
- The text size in Figure 9 is very small.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors,

the paper need to be significantly improved. It is hard to read in its current version. Specifically, the following should be taken into consideration:

• you are using informal words and language in many occasions. You are encouraged to use more formal language.
• the writing style is not concise with too many grammatical and punctuation mistakes. I advice that the manuscript be read by a native English speaker for proof.
• expand the abbreviations in their first mention.
• the abstract need to be rewritten. the sequence is not clear. start by intro, then describing the problem clearly, thereafter the contributions and their significance.
• the organization of the paper is confusing. Reorder subsections and sections accordingly.
• the titles of the sections and subsections are not convenient. rename.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf