Add InputValidator utility for score range checks

src/main/java/com/preponderous/parpt/command/CreateProjectCommand.java

@@ -6,6 +6,7 @@
 import com.preponderous.parpt.score.ScoreCalculator;
 import com.preponderous.parpt.service.ProjectService;
 import com.preponderous.parpt.util.ConsoleInputProvider;
+import com.preponderous.parpt.util.InputValidator;
 import org.springframework.shell.standard.ShellComponent;
 import org.springframework.shell.standard.ShellMethod;
 import org.springframework.shell.standard.ShellOption;
@@ -56,7 +57,7 @@ private int getAverageScore(String[] prompts) throws InvalidScoreException, Crea
         for (String prompt : prompts) {
             try {
                 int score = Integer.parseInt(readInput(prompt));
-                if (score < 1 || score > 5) {
+                if (!InputValidator.isValidScore(score)) {
                     throw new InvalidScoreException("Invalid score. Must be between 1 and 5.");
                 }
                 total += score;
@@ -133,8 +134,7 @@ public String execute(
             return CANCELLED_MESSAGE;
         }
 
-        if (impact < 1 || impact > 5 || confidence < 1 || confidence > 5 ||
-                ease < 1 || ease > 5 || reach < 1 || reach > 5 || effort < 1 || effort > 5) {
+        if (!InputValidator.areValidScores(impact, confidence, ease, reach, effort)) {
             return "All scores must be between 1 and 5.";
         }
 

src/main/java/com/preponderous/parpt/command/UpdateProjectCommand.java

@@ -4,6 +4,7 @@
 import com.preponderous.parpt.repo.ProjectRepository;
 import com.preponderous.parpt.score.ScoreCalculator;
 import com.preponderous.parpt.service.ProjectService;
+import com.preponderous.parpt.util.InputValidator;
 import org.springframework.shell.standard.ShellComponent;
 import org.springframework.shell.standard.ShellMethod;
 import org.springframework.shell.standard.ShellOption;
@@ -21,10 +22,6 @@ public UpdateProjectCommand(ProjectService projectService, ScoreCalculator score
         this.scoreCalculator = scoreCalculator;
     }
 
-    private static boolean isOutOfRange(Integer score) {
-        return score != null && (score < 1 || score > 5);
-    }
-
     @ShellMethod(key = "update", value = "Updates the description or scores of a specific project by name.")
     public String execute(
             @ShellOption(help = "The name of the project to update") String projectName,
@@ -41,7 +38,7 @@ public String execute(
         if (description != null && description.isEmpty()) {
             return "Project description cannot be empty.";
         }
-        if (Stream.of(impact, confidence, ease, reach, effort).anyMatch(UpdateProjectCommand::isOutOfRange)) {
+        if (!InputValidator.areValidScores(impact, confidence, ease, reach, effort)) {
             return "All scores must be between 1 and 5.";
         }
 

src/main/java/com/preponderous/parpt/util/InputValidator.java

@@ -0,0 +1,38 @@
+package com.preponderous.parpt.util;
+
+/**
+ * Validates user-supplied input, so every command applies the same rules.
+ */
+public final class InputValidator {
+    public static final int MIN_SCORE = 1;
+    public static final int MAX_SCORE = 5;
+
+    private InputValidator() {
+    }
+
+    /**
+     * Checks whether a score lies within the allowed range.
+     *
+     * @param score The score to check
+     * @return True if the score is between {@link #MIN_SCORE} and {@link #MAX_SCORE}, inclusive
+     */
+    public static boolean isValidScore(int score) {
+        return score >= MIN_SCORE && score <= MAX_SCORE;
+    }
+
+    /**
+     * Checks whether every given score lies within the allowed range. A null score stands for a
+     * value that was not supplied and is ignored.
+     *
+     * @param scores The scores to check
+     * @return True if no non-null score is outside the allowed range
+     */
+    public static boolean areValidScores(Integer... scores) {
+        for (Integer score : scores) {
+            if (score != null && !isValidScore(score)) {
+                return false;
+            }
+        }
+        return true;
+    }
+}

src/test/java/com/preponderous/parpt/util/InputValidatorTest.java

@@ -0,0 +1,43 @@
+package com.preponderous.parpt.util;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class InputValidatorTest {
+
+    @Test
+    void testScoresWithinRangeAreValid() {
+        for (int score = 1; score <= 5; score++) {
+            assertTrue(InputValidator.isValidScore(score), "Score " + score + " should be valid");
+        }
+    }
+
+    @Test
+    void testScoresOutsideRangeAreInvalid() {
+        assertFalse(InputValidator.isValidScore(0));
+        assertFalse(InputValidator.isValidScore(6));
+        assertFalse(InputValidator.isValidScore(-1));
+        assertFalse(InputValidator.isValidScore(Integer.MAX_VALUE));
+        assertFalse(InputValidator.isValidScore(Integer.MIN_VALUE));
+    }
+
+    @Test
+    void testAllScoresWithinRangeAreValid() {
+        assertTrue(InputValidator.areValidScores(1, 2, 3, 4, 5));
+    }
+
+    @Test
+    void testOneScoreOutsideRangeMakesAllInvalid() {
+        assertFalse(InputValidator.areValidScores(1, 2, 6, 4, 5));
+        assertFalse(InputValidator.areValidScores(0, 2, 3, 4, 5));
+    }
+
+    @Test
+    void testNullScoresAreIgnored() {
+        assertTrue(InputValidator.areValidScores(null, 3, null));
+        assertTrue(InputValidator.areValidScores((Integer) null));
+        assertFalse(InputValidator.areValidScores(null, 6, null));
+    }
+}