Best ways to test PSQL DB - postgresql

Question

Assuming I have the following table, functions and data
create table people (
id bigserial primary key,
age int,
height int,
weight int
);
create or replace function add_person (p_age int, p_height int, p_weight int);
create or replace function get_person_by_age (p_age int);
create or replace function get_person_by_height (p_height int);
create or replace function get_person_by_weight (p_weight int);
add_person (20,180,100);
add_person (20,181,101);
add_person (20,182,102);
add_person (20,183,103);
I am currently testing my database purely in bash so I would have these very long files like so (pseudocode only)
#!/bin/bash
# Insert data
sudo -u postgres psql -d $db_name -c "add_person(20,180,100)"
sudo -u postgres psql -d $db_name -c "add_person(20,181,101)"
sudo -u postgres psql -d $db_name -c "add_person(20,182,102)"
sudo -u postgres psql -d $db_name -c "add_person(20,183,103)"
# Retrieve data
persons=$(sudo -u postgres psql -d $db_name -c "get_person_by_age (20)")
# Count number of rows and make sure it matches the expected outcome
# (You have to manually strip header and footer lines but ignore for now)
if [ $(echo $persons | wc -l) -ne 4]
then
echo "Fail"
exit 1
fi
My test scripts have grown too large and there are so many things I am trying to catch (actions which should throw errors but which do not ie. false positives, actions which should not throw errors but which do ie false negatives, actions which throw errors other than that which they are supposed to, etc.). More importantly, the tests are incredibly slow as bash keeps trying to establish a connection to Postgre.
The reason I am not doing this in PGSQL is because the logic of queries can grow very complex as my db queries have many filters.
Is there a better existing solution to solve my problem? I looked at pgTAP but the documentation for that is horrendous

Answer 1

First of all, I think you could gain a lot of speed by running multiple commands in one client initialization. The "-c" flag only runs one command, and there is some small overhead in starting a connection that really adds up if you are running many commands, as you said.
For example, you could do something like this for your insert commands:
sudo -u postgres psql -d $db_name << EOF
add_person(20,180,100);
add_person(20,181,101);
add_person(20,182,102);
add_person(20,183,103);
Alternatively, you could list all the commands you want to run in a file and run them with "--file"/"-f":
sudo -u postgres psql -d $db_name -f "my_add_commands.psql"
I can't speak to why you are getting false errors, but generally I find that writing complicated test scripts in bash is a pain. If possible, I would consider using any language you are familiar with that has proper try/catch logic and a robust testing library with assertions. This is personally how I write tests for SQL functions. However, you would probably also need to use library that lets you make and process psql queries in the respective language.
There is a light psql testing library for python, but I haven't used it myself. Maybe worth a look though.