tests: Make test writing simpler and add two new tests.

Add a test_todo_session function to test-lib.sh that enables
easy recording of input and output from todo.sh (including
annotation of exit status for testing error cases).

Begin to port and re-factor testsuite.txt into smaller
test cases, starting with basic add list functionality
and replace functionality.

Thanks to Philippe Teuwen <phil@teuwen.org> for feedback
and improvements.

Signed-off-by: Emil Sit <sit@emilsit.net>

tests/t1000-addlist.sh

@@ -0,0 +1,58 @@
+#!/bin/sh
+
+test_description='basic add and list functionality
+
+This test just makes sure the basic add and list
+command work, including support for filtering.
+'
+. ./test-lib.sh
+
+#
+# Add and list
+#
+test_todo_session 'basic add/list' <<EOF
+>>> todo.sh add notice the daisies
+TODO: 'notice the daisies' added on line 1.
+
+>>> todo.sh list
+1 notice the daisies
+--
+TODO: 1 of 1 tasks shown from $HOME/todo.txt
+
+>>> todo.sh add smell the roses
+TODO: 'smell the roses' added on line 2.
+
+>>> todo.sh list
+1 notice the daisies
+2 smell the roses
+--
+TODO: 2 of 2 tasks shown from $HOME/todo.txt
+EOF
+
+#
+# Filter
+#
+test_todo_session 'basic list filtering' <<EOF
+>>> todo.sh list daisies
+1 notice the daisies
+--
+TODO: 1 of 2 tasks shown from $HOME/todo.txt
+
+>>> todo.sh list smell
+2 smell the roses
+--
+TODO: 1 of 2 tasks shown from $HOME/todo.txt
+EOF
+
+test_todo_session 'case-insensitive filtering' <<EOF
+>>> todo.sh add smell the uppercase Roses
+TODO: 'smell the uppercase Roses' added on line 3.
+
+>>> todo.sh list roses
+2 smell the roses
+3 smell the uppercase Roses
+--
+TODO: 2 of 3 tasks shown from $HOME/todo.txt
+EOF
+
+test_done

tests/t1100-replace.sh

@@ -0,0 +1,71 @@
+#!/bin/sh
+
+test_description='basic replace functionality
+
+Ensure we can replace items successfully.
+'
+. ./test-lib.sh
+
+#
+# Set up the basic todo.txt
+#
+todo.sh add notice the daisies > /dev/null
+
+test_todo_session 'replace usage' <<EOF
+>>> todo.sh replace adf asdfa
+=== 1
+usage: $(which todo.sh) replace ITEM# "UPDATED ITEM"
+EOF
+
+test_todo_session 'basic replace' <<EOF
+>>> todo.sh replace 1 "smell the cows"
+1: notice the daisies
+replaced with
+1: smell the cows
+
+>>> todo.sh list
+1 smell the cows
+--
+TODO: 1 of 1 tasks shown from $HOME/todo.txt
+
+>>> todo.sh replace 1 smell the roses
+1: smell the cows
+replaced with
+1: smell the roses
+
+>>> todo.sh list
+1 smell the roses
+--
+TODO: 1 of 1 tasks shown from $HOME/todo.txt
+EOF
+
+cat > todo.txt <<EOF
+smell the cows
+grow some corn
+thrash some hay
+chase the chickens
+EOF
+test_todo_session 'replace in multi-item file' <<EOF
+>>> todo.sh replace 1 smell the cheese
+1: smell the cows
+replaced with
+1: smell the cheese
+
+>>> todo.sh replace 3 jump on hay
+3: thrash some hay
+replaced with
+3: jump on hay
+
+>>> todo.sh replace 4 collect the eggs
+4: chase the chickens
+replaced with
+4: collect the eggs
+EOF
+
+test_todo_session 'replace error' << EOF
+>>> todo.sh replace 10 "hej!"
+=== 1
+10: No such todo.
+EOF
+
+test_done

tests/test-lib.sh

@@ -434,6 +434,60 @@ test_init_todo () {
 	cd "$owd"
 }
 
+# Generate and run a series of tests based on a transcript.
+# Usage: test_todo_session "description" <<EOF
+# >>> command
+# output1
+# output2
+# >>> command
+# === exit status
+# output3
+# output4
+# EOF
+test_todo_session () {
+    test "$#" = 1 ||
+    error "bug in the test script: extra args to test_todo_session"
+    subnum=0
+    cmd=""
+    status=0
+    > expect
+    while read line
+    do
+	case $line in
+	">>> "*)
+	    test -z "$cmd" || error "bug in the test script: missing blank line separator in test_todo_session"
+	    cmd=${line#>>> }
+	    ;;
+	"=== "*)
+	    status=${line#=== }
+	    ;;
+	"")
+	    if [ ! -z "$cmd" ]; then
+		if [ $status = 0 ]; then
+		    test_expect_success "$1 $subnum" "$cmd > output && test_cmp expect output"
+		else
+		    test_expect_success "$1 $subnum" "$cmd > output || test $? = $status && test_cmp expect output"
+		fi
+
+		subnum=$(($subnum + 1))
+		cmd=""
+		status=0
+		> expect
+	    fi
+	    ;;
+	*)
+	    echo $line >> expect
+	    ;;
+	esac
+    done
+    if [ ! -z "$cmd" ]; then
+	if [ $status = 0 ]; then
+	    test_expect_success "$1 $subnum" "$cmd > output && test_cmp expect output"
+	else
+	    test_expect_success "$1 $subnum" "$cmd > output || test $? = $status && test_cmp expect output"
+	fi
+    fi
+}
 
 test_init_todo "$test"
 # Use -P to resolve symlinks in our working directory so that the cwd