diff --git a/flake.nix b/flake.nix
index bef62ee..a39fdce 100644
--- a/flake.nix
+++ b/flake.nix
@@ -20,7 +20,7 @@
 
     checks.x86_64-linux.default = bp.outputs.legacyPackages.x86_64-linux.buildYarnPackage {
         src = ./.;
-        yarnBuildMore = "yarn test";
+        yarnBuildMore = "yarn build; yarn test";
     };
   };
 }
diff --git a/src/index.spec.ts b/src/index.spec.ts
index d53d8d3..6b639db 100644
--- a/src/index.spec.ts
+++ b/src/index.spec.ts
@@ -1,7 +1,7 @@
 import { describe, expect, it } from 'vitest';
 import fc from 'fast-check';
 import {
-  /*afterFirstWord, beforeFirstWord, */ afterFirst, afterLast, endsWith, ltrim, rtrim, trim, startsWith,
+  /*afterFirstWord, beforeFirstWord, */ afterFirst, afterLast, endsWith, ltrim, rtrim, trim, startsWith, beforeFirst,
 } from './index';
 
 describe('strings', () => {
@@ -53,6 +53,16 @@ describe('strings', () => {
             expect(afterLast('&', 'foo bar bat')).toBe('foo bar bat');
         })
     })
+
+    describe('beforeFirst', () => {
+        it('removes everything after the first needle when possible', () => {
+            expect(beforeFirst(' ', 'foo bar bat')).toBe('foo');
+        })
+
+        it('removes everythin when needle is not present', () => {
+            expect(beforeFirst('&', 'foo bar bat')).toBe('');
+        })
+    })
 //   describe('afterFirstWord', () => {
     // it('removes the first word', () => {
     //   fc.assert(fc.property(fc.string(), (str) => {
@@ -67,4 +77,79 @@ describe('strings', () => {
     //   }));
     // });
 //   });
+  describe('ltrim', () => {
+    it('returns input when cutset is empty', () => {
+      expect(ltrim('', 'foo')).toBe('foo');
+    });
+    it('returns empty when input is empty', () => {
+      expect(ltrim('foo', '')).toBe('');
+    });
+    it('can be curried', () => {
+      expect(ltrim('foo', '')).toBe(ltrim('foo')(''));
+      expect(ltrim(' ', ' foo')).toBe(ltrim(' ')(' foo'));
+    });
+    it('trims cutset', () => {
+      fc.assert(fc.property(fc.string(), fc.string(), (cutset, str) => {
+        const got = ltrim(cutset, str);
+
+        if (cutset === '') {
+          expect(got).toBe(str);
+        } else if (str === '') {
+          expect(got).toBe('');
+        } else {
+          if (got === '') {
+            for (const char of str) {
+              expect(cutset).contains(char);
+            }
+          }
+
+          for (const char of cutset) {
+            expect(startsWith(char, got)).toBe(false);
+          }
+        }
+      }));
+    });
+  });
+
+  describe('rtrim', () => {
+    it('returns input when cutset is empty', () => {
+      expect(rtrim('', 'foo')).toBe('foo');
+    });
+    it('returns empty when input is empty', () => {
+      expect(rtrim('foo', '')).toBe('');
+    });
+    it('can be curried', () => {
+      expect(rtrim('foo', '')).toBe(rtrim('foo')(''));
+      expect(rtrim(' ', ' foo')).toBe(rtrim(' ')(' foo'));
+    });
+    it('trims cutset', () => {
+      fc.assert(fc.property(fc.string(), fc.string(), (cutset, str) => {
+        const got = rtrim(cutset, str);
+
+        if (cutset === '') {
+          expect(got).toBe(str);
+        } else if (str === '') {
+          expect(got).toBe('');
+        } else {
+          if (got === '') {
+            for (const char of str) {
+              expect(cutset).contains(char);
+            }
+          }
+
+          for (const char of cutset) {
+            expect(endsWith(char, got)).toBe(false);
+          }
+        }
+      }));
+    });
+  });
+
+  describe('trim', () => {
+    it("composes 'ltrim' and 'rtrim'", function() {
+      fc.assert(fc.property(fc.string(), fc.string(), (cutset, str) => {
+        expect(trim(cutset, str)).toBe(ltrim(cutset, rtrim(cutset, str)));
+      }));
+    });
+  })
 });
\ No newline at end of file
diff --git a/src/index.ts b/src/index.ts
index fa620a9..ca43725 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -18,17 +18,12 @@ export const afterLast = curry(
   (separator: string, str: string) => str.substring(str.lastIndexOf(separator) + 1, str.length),
 );
 
-// export const beforeFirst = curry(
-//   /**
-//    *
-//    * @param {String} separator
-//    * @param {String} str
-//    * @returns {String}
-//    */
-//   (separator, str) => str.substring(0, str.indexOf(separator)),
-// );
+export const beforeFirst = curry(
+  (separator: string, str: string) => str.substring(0, str.indexOf(separator)),
+);
 
-// export const beforeFirstWord = beforeFirst(' ');
+// @todo Test
+export const beforeFirstWord = beforeFirst(' ');
 
 // /**
 //  * @param {String} str