Fix delete command pattern printing and improve test framework

- Add pattern_deleted flag to ProcessingContext to prevent automatic
  pattern printing after 'd', 'D', and 'c' commands
- Fix test framework to properly interpret escape sequences with echo -e
- Correct test expectations for print_line and word_class tests
- Add comprehensive unit tests for delete command behavior

Author: sylvestre

util/run-gnu-testsuite.sh

@@ -225,31 +225,33 @@ run_sed_test() {
     cd "$test_dir"
 
     # Write input to file
-    echo -n "$input_text" > input.txt
-    echo -n "$expected_output" > expected.txt
+    echo -e "$input_text" > input.txt
+    echo -e "$expected_output" > expected.txt
 
     # Run Rust sed
     local rust_exit_code=0
     local rust_output=""
     if [[ -n "$flags" ]]; then
         rust_output=$("$RUST_SED_BIN" "$flags" "$sed_script" input.txt 2>/dev/null) || rust_exit_code=$?
     else
-        rust_output=$(echo -n "$input_text" | "$RUST_SED_BIN" "$sed_script" 2>/dev/null) || rust_exit_code=$?
+        rust_output=$(echo -e "$input_text" | "$RUST_SED_BIN" "$sed_script" 2>/dev/null) || rust_exit_code=$?
     fi
 
     local test_result=""
     local test_status=""
     local error_message=""
 
-    # Compare with expected output
-    if [[ "$rust_output" == "$expected_output" && $rust_exit_code -eq 0 ]]; then
+    # Compare with expected output (interpret escape sequences in expected output too)
+    local expected_interpreted
+    expected_interpreted=$(echo -e "$expected_output")
+    if [[ "$rust_output" == "$expected_interpreted" && $rust_exit_code -eq 0 ]]; then
         log_success "$test_name"
         PASSED_TESTS=$((PASSED_TESTS + 1))
         test_status="PASS"
     else
         log_error "$test_name"
         if [[ "$VERBOSE" == "true" ]]; then
-            echo "  | Expected: '$expected_output'"
+            echo "  | Expected: '$expected_interpreted'"
             echo "  | Got: '$rust_output' (exit: $rust_exit_code)"
         fi
         FAILED_TESTS=$((FAILED_TESTS + 1))
@@ -294,15 +296,15 @@ run_basic_tests() {
     run_sed_test "delete_range" "2,3d" "line1\nline2\nline3\nline4" "line1\nline4"
 
     # Print command
-    run_sed_test "print_line" "-n 2p" "line1\nline2\nline3" "line2" "-n"
+    run_sed_test "print_line" "2p" "line1\nline2\nline3" "line2" "-n"
 
     # Append and insert
     run_sed_test "append" "2a\\inserted" "line1\nline2\nline3" "line1\nline2\ninserted\nline3"
     run_sed_test "insert" "2i\\inserted" "line1\nline2\nline3" "line1\ninserted\nline2\nline3"
 
     # Character classes
     run_sed_test "digit_class" "s/[0-9]/X/g" "abc123def" "abcXXXdef"
-    run_sed_test "word_class" "s/[a-z]/X/g" "Hello123" "XXXXX123"
+    run_sed_test "word_class" "s/[a-z]/X/g" "Hello123" "HXXXX123"
 }
 
 # Run tests from specific GNU testsuite files that have .inp/.good/.sed triplets