[test-improver] Add ConfigManager unit tests (16 edge-case tests)

src/test/java/com/taskflow/util/ConfigManagerTest.java

@@ -0,0 +1,153 @@
+package com.taskflow.util;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Field;
+import java.util.Properties;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * Unit tests for ConfigManager edge-case behaviour.
+ *
+ * ConfigManager is a non-resettable singleton whose internal {@link Properties}
+ * object is only accessible via reflection. Tests manipulate that object
+ * directly, cleaning up in @AfterEach to avoid cross-test pollution.
+ */
+class ConfigManagerTest {
+
+    private static final String TEST_KEY_INT  = "test.configmanager.int";
+    private static final String TEST_KEY_BOOL = "test.configmanager.bool";
+    private static final String TEST_KEY_STR  = "test.configmanager.str";
+
+    // -----------------------------------------------------------------------
+    // Helpers
+    // -----------------------------------------------------------------------
+
+    private Properties getConfigProps() throws Exception {
+        ConfigManager cm = ConfigManager.getInstance();
+        Field f = ConfigManager.class.getDeclaredField("config");
+        f.setAccessible(true);
+        return (Properties) f.get(cm);
+    }
+
+    private void setProperty(String key, String value) throws Exception {
+        getConfigProps().setProperty(key, value);
+    }
+
+    @AfterEach
+    void cleanup() throws Exception {
+        Properties props = getConfigProps();
+        props.remove(TEST_KEY_INT);
+        props.remove(TEST_KEY_BOOL);
+        props.remove(TEST_KEY_STR);
+    }
+
+    // -----------------------------------------------------------------------
+    // get(String key) and get(String key, String defaultValue)
+    // -----------------------------------------------------------------------
+
+    @Test
+    void get_missingKey_returnsNull() {
+        assertNull(ConfigManager.getInstance().get(TEST_KEY_STR));
+    }
+
+    @Test
+    void get_presentKey_returnsValue() throws Exception {
+        setProperty(TEST_KEY_STR, "hello");
+        assertEquals("hello", ConfigManager.getInstance().get(TEST_KEY_STR));
+    }
+
+    @Test
+    void get_missingKeyWithDefault_returnsDefault() {
+        assertEquals("fallback", ConfigManager.getInstance().get(TEST_KEY_STR, "fallback"));
+    }
+
+    @Test
+    void get_presentKeyWithDefault_returnsValue() throws Exception {
+        setProperty(TEST_KEY_STR, "actual");
+        assertEquals("actual", ConfigManager.getInstance().get(TEST_KEY_STR, "fallback"));
+    }
+
+    // -----------------------------------------------------------------------
+    // getInt
+    // -----------------------------------------------------------------------
+
+    @Test
+    void getInt_missingKey_returnsDefault() {
+        assertEquals(42, ConfigManager.getInstance().getInt(TEST_KEY_INT, 42));
+    }
+
+    @Test
+    void getInt_validIntValue_returnsParsedInt() throws Exception {
+        setProperty(TEST_KEY_INT, "7");
+        assertEquals(7, ConfigManager.getInstance().getInt(TEST_KEY_INT, 0));
+    }
+
+    @Test
+    void getInt_negativeIntValue_returnsParsedInt() throws Exception {
+        setProperty(TEST_KEY_INT, "-5");
+        assertEquals(-5, ConfigManager.getInstance().getInt(TEST_KEY_INT, 0));
+    }
+
+    @Test
+    void getInt_nonNumericValue_returnsDefault() throws Exception {
+        setProperty(TEST_KEY_INT, "not-a-number");
+        assertEquals(99, ConfigManager.getInstance().getInt(TEST_KEY_INT, 99));
+    }
+
+    @Test
+    void getInt_decimalValue_returnsDefault() throws Exception {
+        // Integer.parseInt("3.14") throws NumberFormatException → default
+        setProperty(TEST_KEY_INT, "3.14");
+        assertEquals(0, ConfigManager.getInstance().getInt(TEST_KEY_INT, 0));
+    }
+
+    @Test
+    void getInt_emptyString_returnsDefault() throws Exception {
+        setProperty(TEST_KEY_INT, "");
+        assertEquals(5, ConfigManager.getInstance().getInt(TEST_KEY_INT, 5));
+    }
+
+    // -----------------------------------------------------------------------
+    // getBoolean
+    // -----------------------------------------------------------------------
+
+    @Test
+    void getBoolean_missingKey_returnsDefault() {
+        assertTrue(ConfigManager.getInstance().getBoolean(TEST_KEY_BOOL, true));
+        assertFalse(ConfigManager.getInstance().getBoolean(TEST_KEY_BOOL, false));
+    }
+
+    @Test
+    void getBoolean_trueString_returnsTrue() throws Exception {
+        setProperty(TEST_KEY_BOOL, "true");
+        assertTrue(ConfigManager.getInstance().getBoolean(TEST_KEY_BOOL, false));
+    }
+
+    @Test
+    void getBoolean_trueStringCaseInsensitive_returnsTrue() throws Exception {
+        setProperty(TEST_KEY_BOOL, "TRUE");
+        assertTrue(ConfigManager.getInstance().getBoolean(TEST_KEY_BOOL, false));
+    }
+
+    @Test
+    void getBoolean_falseString_returnsFalse() throws Exception {
+        setProperty(TEST_KEY_BOOL, "false");
+        assertFalse(ConfigManager.getInstance().getBoolean(TEST_KEY_BOOL, true));
+    }
+
+    /** Boolean.parseBoolean treats anything other than "true" (case-insensitive) as false. */
+    @Test
+    void getBoolean_yesString_returnsFalse() throws Exception {
+        setProperty(TEST_KEY_BOOL, "yes");
+        assertFalse(ConfigManager.getInstance().getBoolean(TEST_KEY_BOOL, true));
+    }
+
+    @Test
+    void getBoolean_numericOne_returnsFalse() throws Exception {
+        setProperty(TEST_KEY_BOOL, "1");
+        assertFalse(ConfigManager.getInstance().getBoolean(TEST_KEY_BOOL, true));
+    }
+}