Falderal Test: Variable substitution

Tests for variable substitution, and quoting rules during such.

Note that Falderal is responsible for quoting the substitution text of all %(...) variables occurring in a shell command template; it is not necessary to put any quotes around them in the template string.

-> Functionality "Echo Body" is implemented by shell command
-> "python3 echo.py %(test-body-text)"

-> Tests for functionality "Echo Body"

| foo
+ bar
= foo

Single quotes in the test body text are single escaped.

| don't
+ can't
= don't

-> Functionality "Echo Input" is implemented by shell command
-> "python3 echo.py %(test-input-text)"

-> Tests for functionality "Echo Input"

| foo
+ bar
= bar

Single quotes in the test input text are single escaped.

| don't
+ can't
= can't

Note that when variables are expanded, backslash sequences in the replacement string ("\n", etc) are not expanded.

-> Tests for functionality "Echo Body"

| he\nl\tl\\o
= he\nl\tl\\o

The rule that Falderal is responsible for quoting text substituted into the command template extends to %(test-body-file) and %(test-input-file) and %(output-file) as well.

-> Functionality "Cat, from file" is implemented by
-> shell command "python3 cat.py -f %(test-body-file)"

-> Tests for functionality "Cat, from file"

| hello
= hello

| hi
| hi
= hi
= hi

-> Functionality "Cat, to file" is implemented by
-> shell command "python3 cat.py -o %(output-file)"

-> Tests for functionality "Cat, to file"

| hello
= hello

| hi
| hi
= hi
= hi

-> Functionality "Cat, to and from file" is implemented by
-> shell command "python3 cat.py -f %(test-body-file) -o %(output-file)"

-> Tests for functionality "Cat, to and from file"

| hello
= hello

| hi
| hi
= hi
= hi

-> Functionality "Cat input, from file" is implemented by
-> shell command "python3 cat.py -f %(test-input-file)"

-> Tests for functionality "Cat input, from file"

| hekko
+ hello
= hello

| hj
| hj
+ hi
+ hi
= hi
= hi