diff --git a/package.json b/package.json
index f57f1c9..7f4b782 100644
--- a/package.json
+++ b/package.json
@@ -44,7 +44,7 @@
   },
   "scripts": {
     "build:types": "tsc -p ./tsconfig.build.json",
-    "coverage": "vitest run --coverage",
+    "coverage": "vitest run --coverage --coverage.include=src",
     "lint": "eslint",
     "lint:fix": "eslint --fix",
     "prepare": "npm run build:types",
diff --git a/src/plain.js b/src/plain.js
index e5bd8ae..ce2a367 100644
--- a/src/plain.js
+++ b/src/plain.js
@@ -60,7 +60,7 @@ function writePlainBoolean(writer, values) {
  */
 function writePlainInt32(writer, values) {
   for (const value of values) {
-    if (typeof value !== 'number') throw new Error('parquet expected number value')
+    if (!Number.isSafeInteger(value)) throw new Error('parquet expected integer value')
     writer.appendInt32(value)
   }
 }
@@ -110,7 +110,7 @@ function writePlainByteArray(writer, values) {
       bytes = new TextEncoder().encode(value)
     }
     if (!(bytes instanceof Uint8Array)) {
-      throw new Error('parquet byte array expected Uint8Array value')
+      throw new Error('parquet expected Uint8Array value')
     }
     writer.appendUint32(bytes.length)
     writer.appendBytes(bytes)
diff --git a/test/plain.test.js b/test/plain.test.js
index 8ce90b4..c627fc7 100644
--- a/test/plain.test.js
+++ b/test/plain.test.js
@@ -80,10 +80,7 @@ describe('writePlain', () => {
   it('writes BYTE_ARRAY', () => {
     const writer = new ByteWriter()
     const strings = ['a', 'b', 'c', 'd']
-    // strings must be pre-converted to Uint8Array
-    const encoder = new TextEncoder()
-    const bytes = strings.map(s => encoder.encode(s))
-    writePlain(writer, bytes, 'BYTE_ARRAY')
+    writePlain(writer, strings, 'BYTE_ARRAY')
 
     let offset = 0
     for (const s of strings) {
@@ -98,9 +95,43 @@ describe('writePlain', () => {
     }
   })
 
+  it('writes FIXED_LENGTH_BYTE_ARRAY', () => {
+    const writer = new ByteWriter()
+    const encoder = new TextEncoder()
+    const strings = ['abcd', 'efgh', 'ijkl']
+      .map(s => encoder.encode(s))
+    writePlain(writer, strings, 'FIXED_LEN_BYTE_ARRAY')
+
+    let offset = 0
+    for (const s of strings) {
+      for (let i = 0; i < s.length; i++) {
+        expect(writer.view.getUint8(offset)).toBe(s[i])
+        offset += 1
+      }
+    }
+  })
+
   it('throws error on unsupported type', () => {
     const writer = new ByteWriter()
     expect(() => writePlain(writer, [1, 2, 3], 'INT96'))
       .toThrow(/parquet unsupported type/i)
   })
+
+  it('throws error on type mismatch', () => {
+    const writer = new ByteWriter()
+    expect(() => writePlain(writer, [1, 2, 3], 'BOOLEAN'))
+      .toThrow('parquet expected boolean value')
+    expect(() => writePlain(writer, [1, 2, 3.5], 'INT32'))
+      .toThrow('parquet expected integer value')
+    expect(() => writePlain(writer, [1n, 2n, 3], 'INT64'))
+      .toThrow('parquet expected bigint value')
+    expect(() => writePlain(writer, [1, 2, 3n], 'FLOAT'))
+      .toThrow('parquet expected number value')
+    expect(() => writePlain(writer, [1, 2, 3n], 'DOUBLE'))
+      .toThrow('parquet expected number value')
+    expect(() => writePlain(writer, [1, 2, 3], 'BYTE_ARRAY'))
+      .toThrow('parquet expected Uint8Array value')
+    expect(() => writePlain(writer, [1, 2, 3], 'FIXED_LEN_BYTE_ARRAY'))
+      .toThrow('parquet expected Uint8Array value')
+  })
 })
diff --git a/test/write.buffer.test.js b/test/write.buffer.test.js
index c2f600e..a8f2882 100644
--- a/test/write.buffer.test.js
+++ b/test/write.buffer.test.js
@@ -32,6 +32,12 @@ describe('parquetWriteBuffer', () => {
     ])
   })
 
+  it('serializes a string without converted_type', () => {
+    const data = ['string1', 'string2', 'string3']
+    const file = parquetWriteBuffer({ columnData: [{ name: 'string', data, type: 'BYTE_ARRAY' }] })
+    expect(file.byteLength).toBe(162)
+  })
+
   it('efficiently serializes sparse booleans', async () => {
     const bool = Array(10000).fill(null)
     bool[10] = true
@@ -187,8 +193,20 @@ describe('parquetWriteBuffer', () => {
   })
 
   it('throws for wrong type specified', () => {
-    expect(() => parquetWriteBuffer({ columnData: [{ name: 'int', data: [1, 2, 3], type: 'BOOLEAN' }] }))
-      .toThrow('parquet expected boolean value')
+    expect(() => parquetWriteBuffer({ columnData: [{ name: 'int', data: [1, 2, 3], type: 'INT64' }] }))
+      .toThrow('parquet expected bigint value')
+    expect(() => parquetWriteBuffer({ columnData: [{ name: 'int', data: [1n, 2n, 3n], type: 'INT32' }] }))
+      .toThrow('parquet expected integer value')
+    expect(() => parquetWriteBuffer({ columnData: [{ name: 'int', data: [1, 2, 3n], type: 'INT32' }] }))
+      .toThrow('parquet expected integer value')
+    expect(() => parquetWriteBuffer({ columnData: [{ name: 'int', data: [1, 2, 3.5], type: 'INT32' }] }))
+      .toThrow('parquet expected integer value')
+    expect(() => parquetWriteBuffer({ columnData: [{ name: 'int', data: [1n, 2n, 3n], type: 'FLOAT' }] }))
+      .toThrow('parquet expected number value')
+    expect(() => parquetWriteBuffer({ columnData: [{ name: 'int', data: [1n, 2n, 3n], type: 'DOUBLE' }] }))
+      .toThrow('parquet expected number value')
+    expect(() => parquetWriteBuffer({ columnData: [{ name: 'int', data: [1, 2, 3], type: 'BYTE_ARRAY' }] }))
+      .toThrow('parquet expected Uint8Array value')
   })
 
   it('throws for empty column with no type specified', () => {