Add StartsWithStringMatcher

2 files changed, 40 insertions, 0 deletions

diff --git a/src/main/java/org/zwobble/mammoth/internal/styles/StartsWithStringMatcher.java b/src/main/java/org/zwobble/mammoth/internal/styles/StartsWithStringMatcher.java
new file mode 100644
index 0000000..f3a8715
--- /dev/null
+++ b/src/main/java/org/zwobble/mammoth/internal/styles/StartsWithStringMatcher.java
@@ -0,0 +1,14 @@
+package org.zwobble.mammoth.internal.styles;
+
+public class StartsWithStringMatcher implements StringMatcher {
+    private final String prefix;
+
+    public StartsWithStringMatcher(String prefix) {
+        this.prefix = prefix;
+    }
+
+    @Override
+    public boolean matches(String value) {
+        return value.regionMatches(true, 0, prefix, 0, prefix.length());
+    }
+}
diff --git a/src/test/java/org/zwobble/mammoth/tests/styles/StartsWithStringMatcherTests.java b/src/test/java/org/zwobble/mammoth/tests/styles/StartsWithStringMatcherTests.java
new file mode 100644
index 0000000..fd29da1
--- /dev/null
+++ b/src/test/java/org/zwobble/mammoth/tests/styles/StartsWithStringMatcherTests.java
@@ -0,0 +1,26 @@
+package org.zwobble.mammoth.tests.styles;
+
+import org.junit.Test;
+import org.zwobble.mammoth.internal.styles.StartsWithStringMatcher;
+import org.zwobble.mammoth.internal.styles.StringMatcher;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.equalTo;
+
+public class StartsWithStringMatcherTests {
+    @Test
+    public void matchesStringWithPrefix() {
+        StringMatcher matcher = new StartsWithStringMatcher("Heading");
+        assertThat(matcher.matches("Heading"), equalTo(true));
+        assertThat(matcher.matches("Heading 1"), equalTo(true));
+        assertThat(matcher.matches("Custom Heading"), equalTo(false));
+        assertThat(matcher.matches("Head"), equalTo(false));
+        assertThat(matcher.matches("Header 2"), equalTo(false));
+    }
+
+    @Test
+    public void isCaseInsensitive() {
+        StringMatcher matcher = new StartsWithStringMatcher("Heading");
+        assertThat(matcher.matches("heaDING"), equalTo(true));
+    }
+}