Refactor ffoo_import test inc. docstrings

...so that it can be understood by future reader.

test/tests/ffoo_import/TF_RUN

@@ -33,11 +33,12 @@ ignored() {
     echo FFOO_VERSION
 }
 
-print_listing_code() {
+mksnippet() {
     #
-    # Print the code that stores the listing we need to compare
+    # Produce a snippet to store env info to a file $1
     #
-    # This will be included into the mini-test.
+    # File _ignored_ is used as list of tokens to always
+    # remove from the info.
     #
     local target=$1
     printf "
@@ -50,24 +51,37 @@ print_listing_code() {
         " $target
 }
 
-assemble_test_script() {
+wrap_test() {
     #
-    # Assemble test script from listing code and import code
+    # Assemble and print test script code
     #
-    # Assemble test script by including listing code, importing
-    # code and listing code again.  Final script should generate
-    # $1.before and $2.after
+    # Assemble test script by including scanning snippet,
+    # importing code from file $1, and snippet again.  If run,
+    # the code printed by this function will generate two
+    # files: $1.before and $1.after.
     #
     local name=$1
-    print_listing_code $name.before
+    mksnippet $name.before
     cat "$name" \
       | sed -e "s|\\<ffoom\\>|$ffoom_path|"   # << since PATH may be empty
-    print_listing_code $name.after
+    mksnippet $name.after
 }
 
 tf_do_subtest() {
+    #
+    # Prepare, run and check results of test $1
+    #
+    # Contents of $1 file (which is supposed to be importing
+    # code) are altered for testing and wrapped so that on
+    # execution in clean environment, two files are produced to
+    # hold sets of detected variable and function names--before
+    # import and after it.
+    #
+    # The difference of the sets (i.e. what we have *really*
+    # imported) must be same as $1.oracle.
+    #
     local name=$1
-    assemble_test_script $name > $name.sh
+    wrap_test $name > $name.sh
     env -i bash $name.sh
     comm -13 $name.before $name.after > $name.new
     # i.e. lines introduced by import ^^