added test-script for expr

Author: JebediahS

chapter_5/exercise_5_10/expr_test.sh

@@ -0,0 +1,87 @@
+#!/bin/bash
+
+# check if file is present and executable
+if [ ! -f expr ]; then
+    echo "File 'expr' found!"
+    exit 1
+fi
+
+if [ ! -x expr ]; then
+    echo "File 'expr' not executable!"
+    exit 1
+fi
+
+echo "=== Testing expr calculator ==="
+
+# Test 1: Simple addition
+T=1
+result=$(./expr 2 3 +)
+expected="result: 5.000"
+if [[ "$result" == "$expected" ]]; then
+    echo "Test $T PASS: 2 + 3 = 5"
+else
+    echo "Test $T FAIL: Expected '$expected', got '$result'"
+fi
+
+# Test 2: Commutativity of addition
+T=2
+result=$(./expr 3 2 +)
+expected="result: 5.000"
+if [[ "$result" == "$expected" ]]; then
+    echo "Test $T PASS: 3 + 2 = 5"
+else
+    echo "Test $T FAIL: Expected '$expected', got '$result'"
+fi
+
+# Test 3: Subtraction
+T=3
+result=$(./expr 10 3 -)
+expected="result: 7.000"
+if [[ "$result" == "$expected" ]]; then
+    echo "Test $T PASS: 10 - 3 = 7"
+else
+    echo "Test $T FAIL: Expected '$expected', got '$result'"
+fi
+
+# Test 4: Complex expression
+T=4
+# ------------------------------------
+# Expected:
+# 5 --> [5]
+# 1 --> [5, 1]
+# 2 --> [5, 1, 2]
+# + --> (1 + 2 = 3) --> [5, 3]
+# 4 --> [5, 3, 4]
+# * --> (3 * 4 = 12) --> [5, 12]
+# + --> (5 + 12 = 17) --> [17]
+# 3 --> [17, 3]
+# - --> (17 - 3 = 14) --> [14]
+# ------------------------------------
+result=$(./expr 5 1 2 + 4 \* + 3 -)
+expected="result: 14.000"
+if [[ "$result" == "$expected" ]]; then
+    echo "Test $T PASS: Complex RPN expression"
+else
+    echo "Test $T FAIL: Expected '$expected', got '$result'"
+fi
+
+# Test 5: Division by zero
+T=5
+result=$(./expr 5 0 / 2>&1)
+if [[ "$result" == *"division by zero"* ]]; then
+    echo "Test $T PASS: Division by zero detected"
+else
+    echo "Test $T FAIL: Should detect division by zero"
+fi
+
+# Test 6: Missing operator
+T=6
+result=$(./expr 5 1)
+expected="Error: Operator is missing!"
+if [[ "$result" == "$expected" ]]; then
+    echo "Test $T PASS: Missing operator"
+else
+    echo "Test $T FAIL: Expected '$expected', got '$result'"
+fi
+
+echo "=== Tests Complete ==="