test: Run tests for bash and rust implementation of exporter program

[locnnil]

• Depends on: feat: Add func to detect nested values and drop it #27

[locnnil]

The current error is expected:

Error: -e '\n[ERROR] Environment variable '\''ORDER'\'' does not match the expected value, for the app: envtester.app1'
Error: -e '[ERROR] Expected: '\''ORDER=from snap option'\'', but got: '\''ORDER=fromsnapoption'\''\n'

Already reported on:

• Curly brackets, quotation marks and spaces removed from configuration values #31

[farshidtz]

Thanks for improving the tests.
The bash scripts can benefit from some refactoring. The test results contain redundant text.

[farshidtz]

Lines 10 to 49 logically belong to the common script, where the implementation value is verified and consumed.

[farshidtz]

Given the echos, the xtrace makes the results pretty redundant:

[envtester] Setting app-specific env variable
Set env vars: specific to each app
+ snap set envtester apps.app2.env.specific=City
+ echo '[TEST] - Check if the app-specific env var IS SET for the app '\''app1'\'''
+ check_env_exist envtester.app1 HELLO
+ local snap_app=envtester.app1
[TEST] - Check if the app-specific env var IS SET for the app 'app1'
+ local env_name=HELLO
+ eval envtester.app1
++ envtester.app1
+ grep -q '^HELLO='
+ check_env_value envtester.app1 HELLO Hello
+ local snap_app=envtester.app1
+ local env_name=HELLO
+ local exp_value=Hello
+ local actual_value
+ '[' -z HELLO ']'
++ envtester.app1
++ grep '^HELLO='
++ cut -d= -f2-
+ actual_value=Hello
+ '[' Hello '!=' Hello ']'
+ echo -e '\n[TEST] - Check if the app-specific env var IS NOT SET for the app '\''app2'\'''
+ check_env_not_exist envtester.app2 HELLO
+ local snap_app=envtester.app2
+ local env_name=HELLO

[TEST] - Check if the app-specific env var IS NOT SET for the app 'app2'
+ eval envtester.app2
+ grep -q '^HELLO='
++ envtester.app2
+ echo -e '\n[TEST] - Check if the app-specific env var IS SET for the app '\''app2'\'''