diff --git a/.appveyor.yml b/.appveyor.yml
index 57be9e6..e3cfa2a 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -4,6 +4,15 @@ environment:
   matrix:
     - PYTHON_VERSION: 3.7
       MINICONDA: C:\Miniconda3
+    - PYTHON_VERSION: 3.8
+      MINICONDA: C:\Miniconda3
+    - PYTHON_VERSION: 3.9
+      MINICONDA: C:\Miniconda3
+    - PYTHON_VERSION: "3.10"
+      MINICONDA: C:\Miniconda3
+    - PYTHON_VERSION: 3.11
+      MINICONDA: C:\Miniconda3
+
 
 init:
   - ECHO %PYTHON_VERSION% %MINICONDA%
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
new file mode 100644
index 0000000..954bd73
--- /dev/null
+++ b/.github/workflows/tests.yaml
@@ -0,0 +1,44 @@
+name: tests
+
+on:
+  push:
+    paths-ignore:
+      - "README.md"
+      - "docs/**"
+      - "CHANGELOG.md"
+
+  pull_request:
+    paths-ignore:
+      - "README.md"
+      - "docs/*"
+      - "CHANGELOG.md"
+
+jobs:
+  build_biopandas:
+    runs-on: ubuntu-latest
+    # https://github.com/marketplace/actions/setup-miniconda#use-a-default-shell
+    defaults:
+      run:
+        shell: bash -l {0}
+
+    strategy:
+      matrix:
+        python-version: [3.7, 3.8, 3.9, "3.10", 3.11]
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+        # See: https://github.com/marketplace/actions/setup-miniconda
+      - name: Setup miniconda
+        uses: conda-incubator/setup-miniconda@v2
+        with:
+          auto-update-conda: true
+          miniforge-variant: Mambaforge
+          conda-channels: conda-forge
+          python-version: ${{ matrix.python-version }}
+          use-mamba: true
+      - name: Install BioPandas
+        run: pip install -e .
+      - name: Install Dev Dependencies
+        run: pip install mmtf-python numpy scipy pandas pytest looseversion importlib_resources
+      - name: Run unit tests and generate coverage report
+        run: pytest -s -v
diff --git a/biopandas/__init__.py b/biopandas/__init__.py
index ea87b48..0a00907 100644
--- a/biopandas/__init__.py
+++ b/biopandas/__init__.py
@@ -24,5 +24,5 @@
 # 'X.Y.dev0' is the canonical version of 'X.Y.dev'
 #
 
-__version__ = "0.5.1dev"
+__version__ = "0.5.1"
 __author__ = "Sebastian Raschka <mail@sebastianraschka.com>"
diff --git a/biopandas/pdb/pandas_pdb.py b/biopandas/pdb/pandas_pdb.py
index 6eb53bf..94c2ca0 100644
--- a/biopandas/pdb/pandas_pdb.py
+++ b/biopandas/pdb/pandas_pdb.py
@@ -9,8 +9,8 @@
 
 import gzip
 import sys
-import warnings
 import textwrap
+import warnings
 from copy import deepcopy
 from io import StringIO
 from typing import List, Optional
@@ -22,9 +22,10 @@
 import pandas as pd
 from looseversion import LooseVersion
 
-from .engines import amino3to1dict, pdb_df_columns, pdb_records
 from biopandas.constants import ATOMIC_MASSES
 
+from .engines import amino3to1dict, pdb_df_columns, pdb_records
+
 pd_version = LooseVersion(pd.__version__)
 
 
@@ -115,29 +116,34 @@ def read_pdb_from_list(self, pdb_lines):
         self.header, self.code = self._parse_header_code()
         return self
 
-    def fetch_pdb(self, pdb_code: Optional[str] = None, uniprot_id: Optional[str] = None, source: str = "pdb"):
+    def fetch_pdb(
+        self,
+        pdb_code: Optional[str] = None,
+        uniprot_id: Optional[str] = None,
+        source: str = "pdb",
+    ):
         """Fetches PDB file contents from the Protein Databank at rcsb.org or AlphaFold database
-        at https://alphafold.ebi.ac.uk/.
-.
+                at https://alphafold.ebi.ac.uk/.
+        .
 
-        Parameters
-        ----------
-        pdb_code : str, optional
-            A 4-letter PDB code, e.g., `"3eiy"` to retrieve structures from the PDB.
-            Defaults to `None`.
+                Parameters
+                ----------
+                pdb_code : str, optional
+                    A 4-letter PDB code, e.g., `"3eiy"` to retrieve structures from the PDB.
+                    Defaults to `None`.
 
-        uniprot_id : str, optional
-            A UniProt Identifier, e.g., `"Q5VSL9"` to retrieve structures from the AF2 database.
-            Defaults to `None`.
+                uniprot_id : str, optional
+                    A UniProt Identifier, e.g., `"Q5VSL9"` to retrieve structures from the AF2 database.
+                    Defaults to `None`.
 
-        source : str
-            The source to retrieve the structure from
-            (`"pdb"`, `"alphafold2-v3"`, `"alphafold2-v4"`(latest)).
-            Defaults to `"pdb"`.
+                source : str
+                    The source to retrieve the structure from
+                    (`"pdb"`, `"alphafold2-v3"`, `"alphafold2-v4"`(latest)).
+                    Defaults to `"pdb"`.
 
-        Returns
-        ---------
-        self
+                Returns
+                ---------
+                self
 
         """
         # Sanitize input
@@ -145,15 +151,21 @@ def fetch_pdb(self, pdb_code: Optional[str] = None, uniprot_id: Optional[str] =
         invalid_input_identifier_2 = pdb_code is not None and uniprot_id is not None
         invalid_input_combination_1 = uniprot_id is not None and source == "pdb"
         invalid_input_combination_2 = pdb_code is not None and source in {
-            "alphafold2-v3", "alphafold2-v4"}
+            "alphafold2-v3",
+            "alphafold2-v4",
+        }
 
         if invalid_input_identifier_1 or invalid_input_identifier_2:
             raise ValueError("Please provide either a PDB code or a UniProt ID.")
 
         if invalid_input_combination_1:
-            raise ValueError("Please use a 'pdb_code' instead of 'uniprot_id' for source='pdb'.")
+            raise ValueError(
+                "Please use a 'pdb_code' instead of 'uniprot_id' for source='pdb'."
+            )
         elif invalid_input_combination_2:
-            raise ValueError(f"Please use a 'uniprot_id' instead of 'pdb_code' for source={source}.")
+            raise ValueError(
+                f"Please use a 'uniprot_id' instead of 'pdb_code' for source={source}."
+            )
 
         if source == "alphafold2-v3":
             af2_version = 3
@@ -164,8 +176,10 @@ def fetch_pdb(self, pdb_code: Optional[str] = None, uniprot_id: Optional[str] =
         elif source == "pdb":
             self.pdb_path, self.pdb_text = self._fetch_pdb(pdb_code)
         else:
-            raise ValueError(f"Invalid source: {source}."
-                " Please use one of 'pdb' or 'alphafold2-v3' or 'alphafold2-v4'.")
+            raise ValueError(
+                f"Invalid source: {source}."
+                " Please use one of 'pdb' or 'alphafold2-v3' or 'alphafold2-v4'."
+            )
 
         self._df = self._construct_df(pdb_lines=self.pdb_text.splitlines(True))
         return self
@@ -248,7 +262,7 @@ def impute_element(self, records=("ATOM", "HETATM"), inplace=False):
             )
         return t
 
-    def add_remark(self, code, text='', indent=0):
+    def add_remark(self, code, text="", indent=0):
         """Add custom REMARK entry.
 
         The remark will be inserted to preserve the ordering of REMARK codes, i.e. if the code is
@@ -275,57 +289,65 @@ def add_remark(self, code, text='', indent=0):
 
         """
         # Prepare info from self
-        if 'OTHERS' in self.df:
-            df_others = self.df['OTHERS']
+        if "OTHERS" in self.df:
+            df_others = self.df["OTHERS"]
         else:
-            df_others = pd.DataFrame(columns=['record_name', 'entry', 'line_idx'])
-        record_types = list(filter(lambda x: x in self.df, ['ATOM', 'HETATM', 'ANISOU']))
-        remarks = df_others[df_others['record_name'] == 'REMARK']['entry']
+            df_others = pd.DataFrame(columns=["record_name", "entry", "line_idx"])
+        record_types = list(
+            filter(lambda x: x in self.df, ["ATOM", "HETATM", "ANISOU"])
+        )
+        remarks = df_others[df_others["record_name"] == "REMARK"]["entry"]
 
         # Find index and line_idx where to insert the remark to preserve remark code order
         if len(remarks):
             remark_codes = remarks.apply(lambda x: x.split(maxsplit=1)[0]).astype(int)
-            insertion_pos = remark_codes.searchsorted(code, side='right')
+            insertion_pos = remark_codes.searchsorted(code, side="right")
             if insertion_pos < len(remark_codes):  # Remark in the middle
                 insertion_idx = remark_codes.index[insertion_pos]
-                insertion_line_idx = df_others.loc[insertion_idx]['line_idx']
+                insertion_line_idx = df_others.loc[insertion_idx]["line_idx"]
             else:  # Last remark
                 insertion_idx = len(remark_codes)
-                insertion_line_idx = df_others['line_idx'].iloc[-1] + 1
+                insertion_line_idx = df_others["line_idx"].iloc[-1] + 1
         else:  # First remark
             insertion_idx = 0
-            insertion_line_idx = min([self.df[r]['line_idx'].min() for r in record_types])
+            insertion_line_idx = min(
+                [self.df[r]["line_idx"].min() for r in record_types]
+            )
 
         # Wrap remark to fit into 80 characters per line and add indentation
         wrapper = textwrap.TextWrapper(width=80 - (11 + indent))
-        lines = sum([wrapper.wrap(line.strip()) or [' '] for line in text.split('\n')], [])
-        lines = list(map(lambda x: f'{code:4} ' + indent*' ' + x, lines))
+        lines = sum(
+            [wrapper.wrap(line.strip()) or [" "] for line in text.split("\n")], []
+        )
+        lines = list(map(lambda x: f"{code:4} " + indent * " " + x, lines))
 
         # Shift data frame indices and row indices to create space for the remark
         # Create space in OTHERS
-        line_idx = df_others['line_idx'].copy()
+        line_idx = df_others["line_idx"].copy()
         line_idx[line_idx >= insertion_line_idx] += len(lines)
-        df_others['line_idx'] = line_idx
+        df_others["line_idx"] = line_idx
         index = pd.Series(df_others.index.copy())
         index[index >= insertion_idx] += len(lines)
         df_others.index = index
         # Shift all other record types that follow inserted remark
         for records in record_types:
             df_records = self.df[records]
-            if not insertion_line_idx > df_records['line_idx'].max():
-                df_records['line_idx'] += len(lines)
+            if not insertion_line_idx > df_records["line_idx"].max():
+                df_records["line_idx"] += len(lines)
 
         # Put remark into 'OTHERS' data frame
         df_remark = {
-            idx: ['REMARK', line, line_idx]
+            idx: ["REMARK", line, line_idx]
             for idx, line, line_idx in zip(
                 range(insertion_idx, insertion_idx + len(lines)),
                 lines,
                 range(insertion_line_idx, insertion_line_idx + len(lines)),
             )
         }
-        df_remark = pd.DataFrame.from_dict(df_remark, orient='index', columns=df_others.columns)
-        self.df['OTHERS'] = pd.concat([df_others, df_remark]).sort_index()
+        df_remark = pd.DataFrame.from_dict(
+            df_remark, orient="index", columns=df_others.columns
+        )
+        self.df["OTHERS"] = pd.concat([df_others, df_remark]).sort_index()
 
     @staticmethod
     def rmsd(df1, df2, s=None, invert=False, decimals=4):
@@ -435,11 +457,13 @@ def _fetch_af2(uniprot_id: str, af2_version: int = 3):
         try:
             response = urlopen(url)
             txt = response.read()
-            txt = txt.decode('utf-8') if sys.version_info[0] >= 3 else txt.encode('ascii')
+            txt = (
+                txt.decode("utf-8") if sys.version_info[0] >= 3 else txt.encode("ascii")
+            )
         except HTTPError as e:
-            print(f'HTTP Error {e.code}')
+            print(f"HTTP Error {e.code}")
         except URLError as e:
-            print(f'URL Error {e.args}')
+            print(f"URL Error {e.args}")
         return url, txt
 
     def _parse_header_code(self):
@@ -518,7 +542,7 @@ def _construct_df(pdb_lines):
                     record = line[:6].rstrip()
                     line_ele = ["" for _ in range(len(pdb_records[record]) + 1)]
                     for idx, ele in enumerate(pdb_records[record]):
-                        line_ele[idx] = line[ele["line"][0]: ele["line"][1]].strip()
+                        line_ele[idx] = line[ele["line"][0] : ele["line"][1]].strip()
                     line_ele[-1] = line_num
                     line_lists[record].append(line_ele)
                 else:
@@ -847,7 +871,9 @@ def get_model(self, model_index: int) -> PandasPdb:
         biopandas_structure.label_models()
 
         if "ATOM" in biopandas_structure.df.keys():
-            biopandas_structure.df["ATOM"] = biopandas_structure.df["ATOM"].loc[biopandas_structure.df["ATOM"]["model_id"] == model_index]
+            biopandas_structure.df["ATOM"] = biopandas_structure.df["ATOM"].loc[
+                biopandas_structure.df["ATOM"]["model_id"] == model_index
+            ]
         if "HETATM" in biopandas_structure.df.keys():
             biopandas_structure.df["HETATM"] = biopandas_structure.df["HETATM"].loc[
                 biopandas_structure.df["HETATM"]["model_id"] == model_index
@@ -877,15 +903,24 @@ def get_models(self, model_indices: List[int]) -> PandasPdb:
 
         if "ATOM" in biopandas_structure.df.keys():
             biopandas_structure.df["ATOM"] = biopandas_structure.df["ATOM"].loc[
-                [x in model_indices for x in biopandas_structure.df["ATOM"]["model_id"].tolist()]
+                [
+                    x in model_indices
+                    for x in biopandas_structure.df["ATOM"]["model_id"].tolist()
+                ]
             ]
         if "HETATM" in biopandas_structure.df.keys():
             biopandas_structure.df["HETATM"] = biopandas_structure.df["HETATM"].loc[
-                [x in model_indices for x in biopandas_structure.df["HETATM"]["model_id"].tolist()]
+                [
+                    x in model_indices
+                    for x in biopandas_structure.df["HETATM"]["model_id"].tolist()
+                ]
             ]
         if "ANISOU" in biopandas_structure.df.keys():
             biopandas_structure.df["ANISOU"] = biopandas_structure.df["ANISOU"].loc[
-                [x in model_indices for x in biopandas_structure.df["ANISOU"]["model_id"].tolist()]
+                [
+                    x in model_indices
+                    for x in biopandas_structure.df["ANISOU"]["model_id"].tolist()
+                ]
             ]
         return biopandas_structure
 
@@ -906,7 +941,7 @@ def to_pdb_stream(self, records: tuple[str] = ("ATOM", "HETATM")) -> StringIO:
         df = pd.concat([df[a] for a in records])
         if "model_id" in df.columns:
             df = df.drop(columns=["model_id"])
-        df.residue_number = df.residue_number.astype(int)
+        df["residue_number"] = pd.to_numeric(df.residue_number, errors="coerce")
         records = [r.strip() for r in list(set(df.record_name))]
         dfs = {r: df.loc[df.record_name == r] for r in records}
 
@@ -921,8 +956,7 @@ def to_pdb_stream(self, records: tuple[str] = ("ATOM", "HETATM")) -> StringIO:
                 if c in {"x_coord", "y_coord", "z_coord"}:
                     for idx in range(dfs[r][c].values.shape[0]):
                         if len(dfs[r][c].values[idx]) > 8:
-                            dfs[r][c].values[idx] = str(
-                                dfs[r][c].values[idx]).strip()
+                            dfs[r][c].values[idx] = str(dfs[r][c].values[idx]).strip()
 
                 if c not in {"line_idx", "OUT"}:
                     dfs[r]["OUT"] = dfs[r]["OUT"] + dfs[r][c]
@@ -941,7 +975,7 @@ def to_pdb_stream(self, records: tuple[str] = ("ATOM", "HETATM")) -> StringIO:
         output.seek(0)
         return output
 
-    def gyradius(self, records: tuple[str] = ("ATOM",),  decimals: int = 4) -> float:
+    def gyradius(self, records: tuple[str] = ("ATOM",), decimals: int = 4) -> float:
         """Compute the Radius of Gyration of a molecule
 
         Parameters
@@ -958,7 +992,7 @@ def gyradius(self, records: tuple[str] = ("ATOM",),  decimals: int = 4) -> float
         rg : float
             Radius of Gyration of df in Angstrom
 
-            """
+        """
         if isinstance(records, str):
             warnings.warn(
                 "Using a string as `records` argument is "
@@ -970,16 +1004,19 @@ def gyradius(self, records: tuple[str] = ("ATOM",),  decimals: int = 4) -> float
             records = (records,)
 
         if len(records) > 1:
-            df = pd.concat(objs=[self.df[record][["x_coord",
-                                                  "y_coord",
-                                                  "z_coord",
-                                                  "element_symbol"]]
-                                 for record in records])
+            df = pd.concat(
+                objs=[
+                    self.df[record][["x_coord", "y_coord", "z_coord", "element_symbol"]]
+                    for record in records
+                ]
+            )
         else:
             df = self.df[records[0]]
 
         coords = df[["x_coord", "y_coord", "z_coord"]].to_numpy()
-        masses = df["element_symbol"].map(lambda atom: ATOMIC_MASSES.get(atom, 0)).to_numpy()
+        masses = (
+            df["element_symbol"].map(lambda atom: ATOMIC_MASSES.get(atom, 0)).to_numpy()
+        )
         total_mass = masses.sum()
         center_of_mass = (masses[:, None] * coords).sum(axis=0) / total_mass
         distances = np.linalg.norm(coords - center_of_mass, axis=1)
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index 56db5e0..0126fd7 100755
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -1,17 +1,20 @@
 # Release Notes ![](img/logos/3eiy_120.png)
--   Supports `mol` files that have empty lines between blocks, (Via [Ruibin Liu](https://github.com/Ruibin-Liu) PR #[140](https://github.com/BioPandas/biopandas/pull/140#))
+
+- Supports `mol` files that have empty lines between blocks, (Via [Ruibin Liu](https://github.com/Ruibin-Liu) PR #[140](https://github.com/BioPandas/biopandas/pull/140#))
 
 The CHANGELOG for the current development version is available at
 [https://github.com/rasbt/biopandas/blob/main/docs/sources/CHANGELOG.md](https://github.com/rasbt/biopandas/blob/main/docs/sources/CHANGELOG.md).
 
-### 0.5.1dev1 (UNRELEASED)
-
-- Feature: added method to `PandasMmcif` that allow to select by model ids. PR #[145](https://github.com/BioPandas/biopandas/pull/145))
-- Dev: switched testing framework entirely to pytest. Drops nose dependency due to version conflicts with Python 3.12 (`nose`) and 3.8 (`nose`) PR #[146](https://github.com/BioPandas/biopandas/pull/146))
--  Avoid inclusion of test scripts and test data in the PyPI release of the Biopandas library. PR #[148](https://github.com/BioPandas/biopandas/pull/148). Addresses issue [#147](https://github.com/BioPandas/biopandas/issues/147)
+### 0.5.1 (01/08/2024)
 
+- Fix: improves support for writing PDBs with `OTHERS` records to stream. PR [#149](https://github.com/BioPandas/biopandas/pull/149). Addresses issue [#141](https://github.com/BioPandas/biopandas/issues/141).
+- Feature: added method to `PandasMmcif` that allow to select by model ids. PR #[145](https://github.com/BioPandas/biopandas/pull/145)
+- Dev: switched testing framework entirely to pytest. Drops nose dependency due to version conflicts with Python 3.12 (`nose`) and 3.8 (`nose`) PR #[146](https://github.com/BioPandas/biopandas/pull/146)
+- Dev: adds GitHub actions-based CI. PR [#149](https://github.com/BioPandas/biopandas/pull/149).
+- Avoid inclusion of test scripts and test data in the PyPI release of the Biopandas library. PR #[148](https://github.com/BioPandas/biopandas/pull/148). Addresses issue [#147](https://github.com/BioPandas/biopandas/issues/147)
 
 ### 0.5.0dev1 (31/7/2023)
+
 - Implement add_remark for PandasPdb, (Via [Anton Bushuiev](https://github.com/anton-bushuiev) PR #[129](https://github.com/BioPandas/biopandas/pull/129))
 - B_factor shifting one white space issue fix. (Via [Zehra Sarica](https://github.com/zehraacarsarica), PR #[134](https://github.com/BioPandas/biopandas/pull/134))
 - Adds support for pathlib. (Via [Anton Bushuiev](https://github.com/anton-bushuiev), PR #[128](https://github.com/BioPandas/biopandas/pull/128))
@@ -20,7 +23,6 @@ The CHANGELOG for the current development version is available at
 - Improves reliability of parsing multicharacter chain IDs from MMTF files. (Via [Arian Jamasb](https://github.com/a-r-j), PR #[123](https://github.com/rasbt/biopandas/pull/123/files))
 - Replaces null terminator chars in parsed MMTF dataframe with the empty string. (Via [Arian Jamasb](https://github.com/a-r-j), PR #[123](https://github.com/rasbt/biopandas/pull/123/files))
 
-
 ### 0.5.0dev0 (3/4/2023)
 
 ##### Downloads
@@ -37,6 +39,7 @@ The CHANGELOG for the current development version is available at
 - Adds support for parsing [MMTF](https://mmtf.rcsb.org/) files. (via [Arian Jamasb](https://github.com/a-r-j), PR #[111](https://github.com/rasbt/biopandas/pull/111/files))
 - Adds primitive functions for parsing PDB, mmCIF, and MMTF into dataframes. (via [Arian Jamasb](https://github.com/a-r-j), PR #[111](https://github.com/rasbt/biopandas/pull/111/files))
 - Added support for [AlphaFolds 200M+ structures](https://www.deepmind.com/blog/alphafold-reveals-the-structure-of-the-protein-universe) via `PandasMmcif().fetch_mmcif(uniprot_id='Q5VSL9', source='alphafold2-v3')` and `PandasPdb().fetch_pdb(uniprot_id='Q5VSL9', source='alphafold2-v3')`. (Via [Arian Jamasb](https://github.com/a-r-j), PR #[102](https://github.com/rasbt/biopandas/pull/102/files))
+
 ##### Bug Fixes
 
 - Fix the `return` statement in `PandasPdb.to_pdb_stream()` to return `output` instead of `output.seek(0)`. (via [goniochromatic](https://github.com/github.com/goniochromatic/), PR #[116](https://github.com/rasbt/biopandas/pull/116/files))
@@ -44,7 +47,6 @@ The CHANGELOG for the current development version is available at
 - Fix some typos and general style issues. (via [goniochromatic](https://github.com/github.com/goniochromatic/), PR #[116](https://github.com/rasbt/biopandas/pull/116/files))
 - Fix link for "How to contribute" in `README.md`. (via [goniochromatic](https://github.com/github.com/goniochromatic/), PR #[116](https://github.com/rasbt/biopandas/pull/116/files))
 
-
 ### 0.4.1 (05-13-2022)
 
 ##### Downloads
@@ -56,7 +58,6 @@ The CHANGELOG for the current development version is available at
 
 - Remove walrus operator for Python 3.7 compatibility.
 
-
 ### 0.4.0 (05-11-2022)
 
 ##### Downloads
@@ -108,7 +109,7 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
-  - -
+- -
 
 ##### Changes
 
@@ -117,7 +118,7 @@ The CHANGELOG for the current development version is available at
 
 ##### Bug Fixes
 
-  - -
+- -
 
 ### 0.2.8 (03-30-2021)
 
@@ -136,7 +137,7 @@ The CHANGELOG for the current development version is available at
 
 ##### Bug Fixes
 
-  - -
+- -
 
 ### 0.2.7 (08-04-2020)
 
@@ -147,11 +148,11 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
-  - -
+- -
 
 ##### Changes
 
-  - -
+- -
 
 ##### Bug Fixes
 
@@ -166,7 +167,7 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
-  - -
+- -
 
 ##### Changes
 
@@ -175,7 +176,7 @@ The CHANGELOG for the current development version is available at
 
 ##### Bug Fixes
 
-  - -
+- -
 
 ### 0.2.5 (07-09-2019)
 
@@ -186,11 +187,11 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
-  - -
+- -
 
 ##### Changes
 
-  - -
+- -
 
 ##### Bug Fixes
 
@@ -205,7 +206,7 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
-  - -
+- -
 
 ##### Changes
 
@@ -213,7 +214,7 @@ The CHANGELOG for the current development version is available at
 
 ##### Bug Fixes
 
-  - -
+- -
 
 ### 0.2.3 (03-29-2018)
 
@@ -224,7 +225,7 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
-  - -
+- -
 
 ##### Changes
 
@@ -247,7 +248,7 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
-  - -
+- -
 
 ##### Changes
 
@@ -267,7 +268,7 @@ The CHANGELOG for the current development version is available at
 
 ##### New Features
 
-  - -
+- -
 
 ##### Changes
 
@@ -299,7 +300,7 @@ The CHANGELOG for the current development version is available at
 
 ##### Bug Fixes
 
-  - -
+- -
 
 ### 0.1.5 (2016-11-19)
 
@@ -321,7 +322,7 @@ The CHANGELOG for the current development version is available at
 
 ##### Bug Fixes
 
-  - -
+- -
 
 ### 0.1.4 (2015-11-24)
 
diff --git a/tests/mmcif/data/__init__.py b/tests/mmcif/data/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/mmcif/test_read_mmcif.py b/tests/mmcif/test_read_mmcif.py
index e2a907b..a9888ef 100644
--- a/tests/mmcif/test_read_mmcif.py
+++ b/tests/mmcif/test_read_mmcif.py
@@ -11,6 +11,7 @@
     import importlib.resources as pkg_resources
 else:
     import importlib_resources as pkg_resources
+
 from pathlib import Path
 from urllib.error import HTTPError
 
@@ -97,7 +98,6 @@ def test__read_pdb():
     """Test private _read_pdb"""
     ppdb = PandasMmcif()
     _, txt = ppdb._read_mmcif(TESTDATA_FILENAME)
-    print(txt)
     assert txt == three_eiy
 
 
@@ -336,9 +336,7 @@ def test_mmcif_pdb_conversion():
     )
     assert_frame_equal(
         pdb.df["HETATM"].drop(columns=["line_idx"]),
-        mmcif_pdb.df["HETATM"]
-        .drop(columns=["line_idx"])
-        .reset_index(drop=True),
+        mmcif_pdb.df["HETATM"].drop(columns=["line_idx"]).reset_index(drop=True),
     )
 
     # single chain test
@@ -352,7 +350,5 @@ def test_mmcif_pdb_conversion():
     )
     assert_frame_equal(
         pdb.df["HETATM"].drop(columns=["line_idx"]),
-        mmcif_pdb.df["HETATM"]
-        .drop(columns=["line_idx"])
-        .reset_index(drop=True),
+        mmcif_pdb.df["HETATM"].drop(columns=["line_idx"]).reset_index(drop=True),
     )
diff --git a/tests/mmtf/data/__init__.py b/tests/mmtf/data/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/mmtf/test_write_mmtf.py b/tests/mmtf/test_write_mmtf.py
index f516f6c..0aa930b 100644
--- a/tests/mmtf/test_write_mmtf.py
+++ b/tests/mmtf/test_write_mmtf.py
@@ -20,7 +20,6 @@ def test_write_mmtf_bp():
         "1rcf",
     ]
     for pdb in PDB_CODES:
-        print(pdb)
         pm1 = PandasMmtf().fetch_mmtf(pdb)
         pm1.to_mmtf("test.mmtf")
         assert os.path.exists("test.mmtf")
@@ -51,7 +50,6 @@ def test_write_mmtf():
         "1rcf",
     ]
     for pdb in PDB_CODES:
-        print(pdb)
         pm1 = PandasMmtf().fetch_mmtf(pdb)
         write_mmtf(pd.concat([pm1.df["ATOM"], pm1.df["HETATM"]]), "test.mmtf")
         assert os.path.exists("test.mmtf")
diff --git a/tests/mol2/data/__init__.py b/tests/mol2/data/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/pdb/data/__init__.py b/tests/pdb/data/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/pdb/test_amino3to1.py b/tests/pdb/test_amino3to1.py
index 276e2e3..4691906 100644
--- a/tests/pdb/test_amino3to1.py
+++ b/tests/pdb/test_amino3to1.py
@@ -159,7 +159,6 @@ def test_sameindex():
     TESTDATA_1t48 = str(TEST_DATA.joinpath("1t48_995.pdb"))
     p1t48 = PandasPdb()
     p1t48.read_pdb(TESTDATA_1t48)
-    print(p1t48)
     p1t48.df["ATOM"].index = np.zeros(p1t48.df["ATOM"].shape[0], dtype=int)
 
     expect_res = [
@@ -490,12 +489,8 @@ def test_multichain():
     expect_chain = ["A" for _ in range(88)] + ["B" for _ in range(94)]
     got_chain = list(transl["chain_id"].values)
 
-    got_res_a = list(
-        transl.loc[transl["chain_id"] == "A", "residue_name"].values
-    )
-    got_res_b = list(
-        transl.loc[transl["chain_id"] == "B", "residue_name"].values
-    )
+    got_res_a = list(transl.loc[transl["chain_id"] == "A", "residue_name"].values)
+    got_res_b = list(transl.loc[transl["chain_id"] == "B", "residue_name"].values)
 
     assert expect_chain == got_chain
     assert expect_res_a == got_res_a
diff --git a/tests/pdb/test_read_pdb.py b/tests/pdb/test_read_pdb.py
index abb5cdc..4462051 100644
--- a/tests/pdb/test_read_pdb.py
+++ b/tests/pdb/test_read_pdb.py
@@ -11,6 +11,7 @@
     import importlib.resources as pkg_resources
 else:
     import importlib_resources as pkg_resources
+
 from urllib.error import HTTPError
 
 import numpy as np
@@ -94,8 +95,7 @@
 def test__read_pdb():
     """Test private _read_pdb"""
     ppdb = PandasPdb()
-    path, txt = ppdb._read_pdb(TESTDATA_FILENAME)
-    print(txt)
+    _, txt = ppdb._read_pdb(TESTDATA_FILENAME)
     assert txt == three_eiy
 
 
@@ -104,8 +104,7 @@ def test__read_pdb_raises():
     Test if ValueError is raised for wrong file formats."""
 
     expect = (
-        "Wrong file format; allowed file formats are "
-        ".pdb, .pdb.gz, .ent, .ent.gz"
+        "Wrong file format; allowed file formats are " ".pdb, .pdb.gz, .ent, .ent.gz"
     )
 
     def run_code_1():
diff --git a/tests/pdb/test_write_pdb.py b/tests/pdb/test_write_pdb.py
index f16e5ad..7fcc39b 100644
--- a/tests/pdb/test_write_pdb.py
+++ b/tests/pdb/test_write_pdb.py
@@ -10,6 +10,7 @@
     import importlib.resources as pkg_resources
 else:
     import importlib_resources as pkg_resources
+
 import os
 import warnings
 
@@ -51,9 +52,7 @@ def test_defaults():
 def test_nonexpected_column():
     ppdb = PandasPdb()
     ppdb.read_pdb(TESTDATA_FILENAME)
-    ppdb.df["HETATM"]["test"] = pd.Series(
-        "test", index=ppdb.df["HETATM"].index
-    )
+    ppdb.df["HETATM"]["test"] = pd.Series("test", index=ppdb.df["HETATM"].index)
     with warnings.catch_warnings(record=True) as w:
         ppdb.to_pdb(path=OUTFILE, records=["HETATM"])
     with open(OUTFILE, "r") as f:
@@ -159,6 +158,20 @@ def test_b_factor_shift():
     assert tmp_df[
         tmp_df["element_symbol"].isnull() | (tmp_df["element_symbol"] == "")
     ].empty
-    assert not tmp_df[
-        tmp_df["blank_4"].isnull() | (tmp_df["blank_4"] == "")
-    ].empty
+    assert not tmp_df[tmp_df["blank_4"].isnull() | (tmp_df["blank_4"] == "")].empty
+
+
+def test_to_pdb_stream():
+    """Test public write_pdb_stream"""
+    ppdb = PandasPdb()
+    ppdb.read_pdb(TESTDATA_FILENAME)
+    stream = ppdb.to_pdb_stream()
+
+    lines_to_check = open(TESTDATA_FILENAME).read().split("\n")
+    lines_to_check = [
+        line for line in lines_to_check if line.startswith(("ATOM", "HETATM"))
+    ]
+    lines_to_check.append("")
+
+    source_pdb = "\n".join(lines_to_check)
+    assert stream.read() == source_pdb