diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b9a75af..9f5ad6f 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,4 +1,8 @@
 repos:
+-   repo: https://github.com/asottile/pyupgrade
+    rev: v1.23.0
+    hooks:
+    - id: pyupgrade
 -   repo: https://github.com/ambv/black
     rev: stable
     hooks:
diff --git a/docs/source/conf.py b/docs/source/conf.py
index 56dad0b..de7694c 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 #
 # pycounter documentation build configuration file, created by
 # sphinx-quickstart on Thu Nov 13 08:44:21 2014.
@@ -56,8 +55,8 @@
 master_doc = "index"
 
 # General information about the project.
-project = u"pycounter"
-copyright = u"2014-2019, University of Pittsburgh"
+project = "pycounter"
+copyright = "2014-2019, University of Pittsburgh"
 
 # The version info for the project you're documenting, acts as replacement for
 # |version| and |release|, also used in various other places throughout the
@@ -98,7 +97,7 @@
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
-    ("index", "pycounter.tex", u"pycounter Documentation", u"Geoffrey Spear", "manual")
+    ("index", "pycounter.tex", "pycounter Documentation", "Geoffrey Spear", "manual")
 ]
 
 
@@ -106,7 +105,7 @@
 
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [("index", "pycounter", u"pycounter Documentation", [u"Geoffrey Spear"], 1)]
+man_pages = [("index", "pycounter", "pycounter Documentation", ["Geoffrey Spear"], 1)]
 
 # -- Options for Texinfo output -------------------------------------------
 
@@ -117,8 +116,8 @@
     (
         "index",
         "pycounter",
-        u"pycounter Documentation",
-        u"Geoffrey Spear",
+        "pycounter Documentation",
+        "Geoffrey Spear",
         "pycounter",
         "One line description of project.",
         "Miscellaneous",
diff --git a/pycounter/constants.py b/pycounter/constants.py
index 6801b9a..281b170 100644
--- a/pycounter/constants.py
+++ b/pycounter/constants.py
@@ -8,19 +8,19 @@
 }
 
 METRICS = {
-    u"JR1": u"FT Article Requests",
-    u"JR1 GOA": u"Gold Open Access Article Requests",
-    u"BR1": u"Book Title Requests",
-    u"BR2": u"Book Section Requests",
-    u"DB1": [
-        u"Regular Searches",
-        u"Searches-federated and automated",
-        u"Result Clicks",
-        u"Record Views",
+    "JR1": "FT Article Requests",
+    "JR1 GOA": "Gold Open Access Article Requests",
+    "BR1": "Book Title Requests",
+    "BR2": "Book Section Requests",
+    "DB1": [
+        "Regular Searches",
+        "Searches-federated and automated",
+        "Result Clicks",
+        "Record Views",
     ],
-    u"DB2": [
-        u"Access denied: concurrent/simultaneous user license exceeded",
-        u"Access denied: content item not licensed",
+    "DB2": [
+        "Access denied: concurrent/simultaneous user license exceeded",
+        "Access denied: content item not licensed",
     ],
 }
 
@@ -34,165 +34,164 @@
 }
 
 CODES = {
-    u"Database": u"DB",
-    u"Journal": u"JR",
-    u"Book": u"BR",
-    u"Title": u"TR",
-    u"Platform": u"PR",
-    u"Multimedia": u"MR",
-    u"Consortium": u"CR",
+    "Database": "DB",
+    "Journal": "JR",
+    "Book": "BR",
+    "Title": "TR",
+    "Platform": "PR",
+    "Multimedia": "MR",
+    "Consortium": "CR",
 }
 
 # from http://www.niso.org/workrooms/sushi/registry/
 # Not all of these are actually supported by pycounter
 REPORT_DESCRIPTIONS = {
-    u"BR1": u"Number of Successful Title Requests by Month and Title",
-    u"BR2": u"Number of Successful Section Requests by Month and Title",
-    u"BR3": u"Access Denied to Content Items by Month, Title, and Category",
-    u"BR4": u"Access Denied to Content Items by Month, Platform, and Category",
-    u"BR5": u"Total Searches by Month and Title",
-    u"CR1": u"Number of Successful Full-text Journal Article or Book Chapter "
-    u"Requests by Month",
-    u"CR2": u"Total Searches by Month and Database",
-    u"CR3": u"Number of Successful Multimedia Full Content Unit Requests "
-    u"by Month and Collection",
-    u"DB1": u"Total Searches, Result Clicks and Record Views by Month and " u"Database",
-    u"DB2": u"Access Denied by Month, Database and Category",
-    u"JR1": u"Number of Successful Full-Text Article Requests by Month and " u"Journal",
-    u"JR1GOA": u"Number of Successful Gold Open Access Full-Text Article "
-    u"Requests by Month and Journal",
-    u"JR1a": u"Number of Successful Full-Text Article Requests from an "
-    u"Archive by Month and Journal",
-    u"JR2": u"Access Denied to Full Text Articles by Month, Journal, and " u"Category",
-    u"JR3": u"Number of Successful Item Requests and Turnaways by Month, "
-    u"Journal, and Page-Type",
-    u"JR3mobile": u"Number of Successful Item Requests by Month, Journal, "
-    u"and Page-Type for usage on a mobile device",
-    u"JR4": u"Total Searches Run by Month and Collection",
-    u"JR5": u"Number of Successful Full-Text Article Requests by "
-    u"Year-of-Publication (YOP) and Journal",
-    u"MR1": u"Number of Successful Multimedia Full Content Unit Requests "
-    u"by Month and Collection",
-    u"MR2": u"Number of Successful Multimedia Full Content Unit Requests by "
-    u"Month, Collection, and Item Type",
-    u"PR1": u"Total Searches, Result Clicks, and Record Views by Month and "
-    u"Platform",
-    u"TR1": u"Number of Successful Requests for Journal Full-Text Articles "
-    u"and Book Sections by Month and Title",
-    u"TR1mobile": u"Number of Successful Requests for Journal Full-Text "
-    u"Articles and Book Sections by Month and Title "
-    u"(formatted for normal browsers/delivered to mobile "
-    u"devices AND formatted for mobile devices/delivered "
-    u"to mobile devices)",
-    u"TR2": u"Access Denied to Full-Text Items by Month, Title, and Category",
-    u"TR3": u"Number of Successful Item Requests by Month, Title, and " u"Page-Type",
-    u"TR3mobile": u"Number of Successful Item Requests by Month, Title, "
-    u"and Page-Type (formatted for normal browsers/delivered "
-    u"to mobile devices and for mobile devices/delivered to "
-    u"mobile devices)",
-    u"TR_J1": u'Journal Requests (Excluding "OA_Gold")',
+    "BR1": "Number of Successful Title Requests by Month and Title",
+    "BR2": "Number of Successful Section Requests by Month and Title",
+    "BR3": "Access Denied to Content Items by Month, Title, and Category",
+    "BR4": "Access Denied to Content Items by Month, Platform, and Category",
+    "BR5": "Total Searches by Month and Title",
+    "CR1": "Number of Successful Full-text Journal Article or Book Chapter "
+    "Requests by Month",
+    "CR2": "Total Searches by Month and Database",
+    "CR3": "Number of Successful Multimedia Full Content Unit Requests "
+    "by Month and Collection",
+    "DB1": "Total Searches, Result Clicks and Record Views by Month and " "Database",
+    "DB2": "Access Denied by Month, Database and Category",
+    "JR1": "Number of Successful Full-Text Article Requests by Month and " "Journal",
+    "JR1GOA": "Number of Successful Gold Open Access Full-Text Article "
+    "Requests by Month and Journal",
+    "JR1a": "Number of Successful Full-Text Article Requests from an "
+    "Archive by Month and Journal",
+    "JR2": "Access Denied to Full Text Articles by Month, Journal, and " "Category",
+    "JR3": "Number of Successful Item Requests and Turnaways by Month, "
+    "Journal, and Page-Type",
+    "JR3mobile": "Number of Successful Item Requests by Month, Journal, "
+    "and Page-Type for usage on a mobile device",
+    "JR4": "Total Searches Run by Month and Collection",
+    "JR5": "Number of Successful Full-Text Article Requests by "
+    "Year-of-Publication (YOP) and Journal",
+    "MR1": "Number of Successful Multimedia Full Content Unit Requests "
+    "by Month and Collection",
+    "MR2": "Number of Successful Multimedia Full Content Unit Requests by "
+    "Month, Collection, and Item Type",
+    "PR1": "Total Searches, Result Clicks, and Record Views by Month and " "Platform",
+    "TR1": "Number of Successful Requests for Journal Full-Text Articles "
+    "and Book Sections by Month and Title",
+    "TR1mobile": "Number of Successful Requests for Journal Full-Text "
+    "Articles and Book Sections by Month and Title "
+    "(formatted for normal browsers/delivered to mobile "
+    "devices AND formatted for mobile devices/delivered "
+    "to mobile devices)",
+    "TR2": "Access Denied to Full-Text Items by Month, Title, and Category",
+    "TR3": "Number of Successful Item Requests by Month, Title, and " "Page-Type",
+    "TR3mobile": "Number of Successful Item Requests by Month, Title, "
+    "and Page-Type (formatted for normal browsers/delivered "
+    "to mobile devices and for mobile devices/delivered to "
+    "mobile devices)",
+    "TR_J1": 'Journal Requests (Excluding "OA_Gold")',
 }
 
 HEADER_FIELDS = {
     "JR1": (
-        u"Journal",
-        u"Publisher",
-        u"Platform",
-        u"Journal DOI",
-        u"Proprietary Identifier",
-        u"Print ISSN",
-        u"Online ISSN",
-        u"Reporting Period Total",
-        u"Reporting Period HTML",
-        u"Reporting Period PDF",
+        "Journal",
+        "Publisher",
+        "Platform",
+        "Journal DOI",
+        "Proprietary Identifier",
+        "Print ISSN",
+        "Online ISSN",
+        "Reporting Period Total",
+        "Reporting Period HTML",
+        "Reporting Period PDF",
     ),
     "JR2": (
-        u"Journal",
-        u"Publisher",
-        u"Platform",
-        u"Journal DOI",
-        u"Proprietary Identifier",
-        u"Print ISSN",
-        u"Online ISSN",
-        u"Reporting Period Total",
-        u"Reporting Period HTML",
-        u"Reporting Period PDF",
+        "Journal",
+        "Publisher",
+        "Platform",
+        "Journal DOI",
+        "Proprietary Identifier",
+        "Print ISSN",
+        "Online ISSN",
+        "Reporting Period Total",
+        "Reporting Period HTML",
+        "Reporting Period PDF",
     ),
     "JR3": (
-        u"Journal",
-        u"Publisher",
-        u"Platform",
-        u"Journal DOI",
-        u"Proprietary Identifier",
-        u"Print ISSN",
-        u"Online ISSN",
-        u"Reporting Period Total",
-        u"Reporting Period HTML",
-        u"Reporting Period PDF",
+        "Journal",
+        "Publisher",
+        "Platform",
+        "Journal DOI",
+        "Proprietary Identifier",
+        "Print ISSN",
+        "Online ISSN",
+        "Reporting Period Total",
+        "Reporting Period HTML",
+        "Reporting Period PDF",
     ),
     "BR1": (
-        u"",
-        u"Publisher",
-        u"Platform",
-        u"Book DOI",
-        u"Proprietary Identifier",
-        u"ISBN",
-        u"ISSN",
-        u"Reporting Period Total",
+        "",
+        "Publisher",
+        "Platform",
+        "Book DOI",
+        "Proprietary Identifier",
+        "ISBN",
+        "ISSN",
+        "Reporting Period Total",
     ),
     "BR2": (
-        u"",
-        u"Publisher",
-        u"Platform",
-        u"Book DOI",
-        u"Proprietary Identifier",
-        u"ISBN",
-        u"ISSN",
-        u"Reporting Period Total",
+        "",
+        "Publisher",
+        "Platform",
+        "Book DOI",
+        "Proprietary Identifier",
+        "ISBN",
+        "ISSN",
+        "Reporting Period Total",
     ),
     "BR3": (
-        u"",
-        u"Publisher",
-        u"Platform",
-        u"Book DOI",
-        u"Proprietary Identifier",
-        u"ISBN",
-        u"ISSN",
-        u"Reporting Period Total",
+        "",
+        "Publisher",
+        "Platform",
+        "Book DOI",
+        "Proprietary Identifier",
+        "ISBN",
+        "ISSN",
+        "Reporting Period Total",
     ),
     "DB1": (
-        u"Database",
-        u"Publisher",
-        u"Platform",
-        u"User Activity",
-        u"Reporting Period Total",
+        "Database",
+        "Publisher",
+        "Platform",
+        "User Activity",
+        "Reporting Period Total",
     ),
     "DB2": (
-        u"Database",
-        u"Publisher",
-        u"Platform",
-        u"Access denied category",
-        u"Reporting Period Total",
+        "Database",
+        "Publisher",
+        "Platform",
+        "Access denied category",
+        "Reporting Period Total",
     ),
-    "PR1": (u"Platform", u"Publisher", u"User Activity", u"Reporting Period Total"),
+    "PR1": ("Platform", "Publisher", "User Activity", "Reporting Period Total"),
     # FIXME: this is outputting counter 5 reports in 4 format for... reasons.
     "TR_J1": (
-        u"Journal",
-        u"Publisher",
-        u"Platform",
-        u"Journal DOI",
-        u"Proprietary Identifier",
-        u"Print ISSN",
-        u"Online ISSN",
-        u"Reporting Period Total",
-        u"Reporting Period HTML",
-        u"Reporting Period PDF",
+        "Journal",
+        "Publisher",
+        "Platform",
+        "Journal DOI",
+        "Proprietary Identifier",
+        "Print ISSN",
+        "Online ISSN",
+        "Reporting Period Total",
+        "Reporting Period HTML",
+        "Reporting Period PDF",
     ),
 }
 
 TOTAL_TEXT = {
-    "JR1": u"Total for all journals",
-    "BR1": u"Total for all titles",
-    "BR2": u"Total for all titles",
-    "DB2": u"Total for all databases",
+    "JR1": "Total for all journals",
+    "BR1": "Total for all titles",
+    "BR2": "Total for all titles",
+    "DB2": "Total for all databases",
 }
diff --git a/pycounter/exceptions.py b/pycounter/exceptions.py
index e855c93..cea3fa9 100644
--- a/pycounter/exceptions.py
+++ b/pycounter/exceptions.py
@@ -17,7 +17,7 @@ class SushiException(PycounterException):
     """Base class for SUSHI-related exceptions."""
 
     def __init__(self, message, raw=None, xml=None):
-        super(SushiException, self).__init__(message)
+        super().__init__(message)
         self.raw = raw
         self.xml = xml
 
@@ -59,7 +59,7 @@ class Sushi5Error(SushiException):
     """
 
     def __init__(self, message, severity, code):
-        super(Sushi5Error, self).__init__(message)
+        super().__init__(message)
         self.message = message
         self.severity = severity
         self.code = code
diff --git a/pycounter/report.py b/pycounter/report.py
index ee2afe8..45cbc2f 100644
--- a/pycounter/report.py
+++ b/pycounter/report.py
@@ -25,7 +25,7 @@
 )
 
 
-class CounterReport(object):
+class CounterReport:
     """
     a COUNTER usage statistics report.
 
@@ -84,11 +84,8 @@ def __init__(
         self.section_type = section_type
 
     def __repr__(self):
-        return "<CounterReport %s version %s for date range %s to %s>" % (
-            self.report_type,
-            self.report_version,
-            self.period[0],
-            self.period[1],
+        return "<CounterReport {} version {} for date range {} to {}>".format(
+            self.report_type, self.report_version, self.period[0], self.period[1]
         )
 
     def __iter__(self):
@@ -130,25 +127,22 @@ def as_generic(self):
             if code == self.report_type[0:2]:
                 rep_type = name
 
-        report_name = "%s Report %s (R%s)" % (
-            rep_type,
-            self.report_type[-1],
-            self.report_version,
+        report_name = "{} Report {} (R{})".format(
+            rep_type, self.report_type[-1], self.report_version
         )
         output_lines.append([report_name, REPORT_DESCRIPTIONS[self.report_type]])
         if self.report_type == "BR2":
-            output_lines.append([self.customer, u"Section Type:"])
+            output_lines.append([self.customer, "Section Type:"])
             output_lines.append([self.institutional_identifier, self.section_type])
         else:
             output_lines.append([self.customer])
             output_lines.append([self.institutional_identifier])
-        output_lines.append([u"Period covered by Report:"])
-        period = "%s to %s" % (
-            self.period[0].strftime("%Y-%m-%d"),
-            self.period[1].strftime("%Y-%m-%d"),
+        output_lines.append(["Period covered by Report:"])
+        period = "{} to {}".format(
+            self.period[0].strftime("%Y-%m-%d"), self.period[1].strftime("%Y-%m-%d")
         )
         output_lines.append([period])
-        output_lines.append([u"Date run:"])
+        output_lines.append(["Date run:"])
         output_lines.append([self.date_run.strftime("%Y-%m-%d")])
         output_lines.append(self._table_header())
         if self.report_type in ("JR1", "BR1", "BR2", "DB2"):
@@ -168,7 +162,7 @@ def as_generic(self):
     def _totals_lines(self):
         """Generate Totals for COUNTER report, as list of lists of cells."""
         total_lines = []
-        metrics = set(resource.metric for resource in self.pubs)
+        metrics = {resource.metric for resource in self.pubs}
 
         for metric in sorted(metrics):
             total_lines.append(self._totals_line(metric))
@@ -178,18 +172,18 @@ def _totals_lines(self):
     def _totals_line(self, metric):
         """Generate Totals for a given metric."""
         total_cells = [TOTAL_TEXT[self.report_type]]
-        publishers = set(resource.publisher for resource in self.pubs)
+        publishers = {resource.publisher for resource in self.pubs}
         if len(publishers) == 1:
             total_cells.append(publishers.pop())
         else:
-            total_cells.append(u"")
-        platforms = set(resource.platform for resource in self.pubs)
+            total_cells.append("")
+        platforms = {resource.platform for resource in self.pubs}
         if len(platforms) == 1:
             total_cells.append(platforms.pop())
         else:
-            total_cells.append(u"")
+            total_cells.append("")
         if self.report_type in ("JR1", "BR1", "BR2"):
-            total_cells.extend([u""] * 4)
+            total_cells.extend([""] * 4)
         elif self.report_type == "DB2":
             total_cells.append(metric)
         total_usage = 0
@@ -350,7 +344,7 @@ class CounterJournal(CounterEresource):
     def __init__(
         self,
         period=None,
-        metric=METRICS[u"JR1"],
+        metric=METRICS["JR1"],
         issn=None,
         eissn=None,
         month_data=None,
@@ -362,9 +356,7 @@ def __init__(
         doi="",
         proprietary_id="",
     ):
-        super(CounterJournal, self).__init__(
-            period, metric, month_data, title, platform, publisher
-        )
+        super().__init__(period, metric, month_data, title, platform, publisher)
         self.html_total = html_total
         self.pdf_total = pdf_total
         self.doi = doi
@@ -448,9 +440,7 @@ def __init__(
         print_isbn=None,
         online_isbn=None,
     ):
-        super(CounterBook, self).__init__(
-            period, metric, month_data, title, platform, publisher
-        )
+        super().__init__(period, metric, month_data, title, platform, publisher)
         self.eissn = None
         self.doi = doi
         self.proprietary_id = proprietary_id
@@ -462,7 +452,7 @@ def __init__(
         if issn is not None:
             self.issn = issn
         else:
-            self.issn = u""
+            self.issn = ""
 
     def __repr__(self):
         return """<CounterBook %s (ISBN: %s), publisher %s,
@@ -485,7 +475,7 @@ def isbn(self):
          online_ISBN and/or print_ISBN, the online one, if any, will be
          returned, otherwise the print.
         """
-        return self._isbn or self.online_isbn or self.print_isbn or u""
+        return self._isbn or self.online_isbn or self.print_isbn or ""
 
     def as_generic(self):
         """Get data for this line as list of COUNTER report cells."""
@@ -521,9 +511,7 @@ def __init__(
         platform="",
         publisher="",
     ):
-        super(CounterDatabase, self).__init__(
-            period, metric, month_data, title, platform, publisher
-        )
+        super().__init__(period, metric, month_data, title, platform, publisher)
         self.isbn = None
 
     def as_generic(self):
@@ -550,7 +538,7 @@ class CounterPlatform(CounterEresource):
     def __init__(
         self, period=None, metric=None, month_data=None, platform="", publisher=""
     ):
-        super(CounterPlatform, self).__init__(
+        super().__init__(
             period=period,
             metric=metric,
             month_data=month_data,
diff --git a/pycounter/sushi.py b/pycounter/sushi.py
index e855ff5..0b2f52c 100644
--- a/pycounter/sushi.py
+++ b/pycounter/sushi.py
@@ -219,7 +219,7 @@ def raw_to_full(raw_report):
     try:
         inst_id = customer.find(".//%s" % ns("counter", "ID")).text
     except AttributeError:
-        inst_id = u""
+        inst_id = ""
     report_data["institutional_identifier"] = inst_id
 
     rep_root = root.find(".//%s" % ns("counter", "Report"))
diff --git a/pycounter/sushiclient.py b/pycounter/sushiclient.py
index 745a0ac..d147dfe 100644
--- a/pycounter/sushiclient.py
+++ b/pycounter/sushiclient.py
@@ -74,7 +74,7 @@ def main(
 ):
     """Main function for the SUSHI client."""
     # pylint: disable=too-many-locals
-    click.echo("pycounter SUSHI client for URL %s (%s R%s)" % (url, report, release))
+    click.echo(f"pycounter SUSHI client for URL {url} ({report} R{release})")
     if end_date is not None and start_date is None:
         click.echo("Cannot specify --end_date without --start_date", err=True)
         sys.exit(1)
diff --git a/pycounter/test/counter5/conftest.py b/pycounter/test/counter5/conftest.py
index 369e1e6..00496dc 100644
--- a/pycounter/test/counter5/conftest.py
+++ b/pycounter/test/counter5/conftest.py
@@ -1,6 +1,5 @@
 """Pytest fixtures for COUNTER 5 test suite."""
 import datetime
-import io
 import os
 
 from httmock import HTTMock, urlmatch
@@ -13,7 +12,7 @@
 def sushi_mock(url_unused, request_unused):
     """Mocked SUSHI service."""
     path = os.path.join(os.path.dirname(__file__), "data", "sushi_simple.json")
-    with io.open(path, "r", encoding="utf-8") as datafile:
+    with open(path, "r", encoding="utf-8") as datafile:
         return datafile.read()
 
 
diff --git a/pycounter/test/counter5/test_sushi.py b/pycounter/test/counter5/test_sushi.py
index 557fcd3..a42ffd2 100644
--- a/pycounter/test/counter5/test_sushi.py
+++ b/pycounter/test/counter5/test_sushi.py
@@ -1,6 +1,5 @@
 """Tests for COUNTER 5 SUSHI support."""
 
-import io
 import os
 
 from httmock import all_requests, HTTMock
@@ -11,7 +10,7 @@
 
 
 def test_report_type(sushi5_report_trj1):
-    assert sushi5_report_trj1.report_type == u"TR_J1"
+    assert sushi5_report_trj1.report_type == "TR_J1"
 
 
 def test_report_version(sushi5_report_trj1):
@@ -19,7 +18,7 @@ def test_report_version(sushi5_report_trj1):
 
 
 def test_report_customer(sushi5_report_trj1):
-    assert sushi5_report_trj1.institutional_identifier == u"exampleLibrary"
+    assert sushi5_report_trj1.institutional_identifier == "exampleLibrary"
 
 
 def test_data(sushi5_report_trj1):
@@ -31,7 +30,7 @@ def test_data(sushi5_report_trj1):
 def test_metric(sushi5_report_trj1):
     publication = next(iter(sushi5_report_trj1))
     metrics = [month[1] for month in publication]
-    assert metrics[0] == u"Total_Item_Requests"
+    assert metrics[0] == "Total_Item_Requests"
 
 
 def test_doi(sushi5_report_trj1):
@@ -43,7 +42,7 @@ def test_doi(sushi5_report_trj1):
 def not_authorized(url_unused, request_unused):
     """Mocked SUSHI service."""
     path = os.path.join(os.path.dirname(__file__), "data", "not_authorized.json")
-    with io.open(path, "r", encoding="utf-8") as datafile:
+    with open(path, "r", encoding="utf-8") as datafile:
         return datafile.read()
 
 
@@ -54,6 +53,6 @@ def test_error_not_authorized():
                 url="https://example.com/sushi", release=5
             )
     exc = exception.value
-    assert exc.message == u"Requestor Not Authorized to Access Service"
+    assert exc.message == "Requestor Not Authorized to Access Service"
     assert exc.severity == "Error"
     assert exc.code == 2000
diff --git a/pycounter/test/test_bad_reports.py b/pycounter/test/test_bad_reports.py
index 16e5f50..60fcef7 100644
--- a/pycounter/test/test_bad_reports.py
+++ b/pycounter/test/test_bad_reports.py
@@ -8,7 +8,7 @@
 import pycounter.exceptions
 
 
-@pytest.mark.parametrize("report_type", [u"Bogus Report 7 (R4)"])
+@pytest.mark.parametrize("report_type", ["Bogus Report 7 (R4)"])
 def test_report_type(report_type):
     """Report type doesn't exist."""
     data = [[report_type]]
diff --git a/pycounter/test/test_br1.py b/pycounter/test/test_br1.py
index a8ce1e6..cb4373f 100644
--- a/pycounter/test/test_br1.py
+++ b/pycounter/test/test_br1.py
@@ -17,12 +17,12 @@ def setUp(self):
         )
 
     def test_reportname(self):
-        self.assertEqual(self.report.report_type, u"BR1")
+        self.assertEqual(self.report.report_type, "BR1")
         self.assertEqual(self.report.report_version, 4)
 
     def test_metric(self):
-        self.assertEqual(self.report.metric, u"Book Title Requests")
+        self.assertEqual(self.report.metric, "Book Title Requests")
 
     def test_isbn(self):
         publication = self.report.pubs[0]
-        self.assertEqual(publication.isbn, u"9787490833809")
+        self.assertEqual(publication.isbn, "9787490833809")
diff --git a/pycounter/test/test_br2.py b/pycounter/test/test_br2.py
index fe18c95..52b906b 100644
--- a/pycounter/test/test_br2.py
+++ b/pycounter/test/test_br2.py
@@ -1,4 +1,3 @@
-# coding: utf-8
 """Test parsing of COUNTER BR2 book report."""
 
 from __future__ import absolute_import
@@ -18,8 +17,8 @@ def setUp(self):
         )
 
     def test_reportname(self):
-        self.assertEqual(self.report.report_type, u"BR2")
+        self.assertEqual(self.report.report_type, "BR2")
         self.assertEqual(self.report.report_version, 4)
 
     def test_metric(self):
-        self.assertEqual(self.report.metric, u"Book Section Requests")
+        self.assertEqual(self.report.metric, "Book Section Requests")
diff --git a/pycounter/test/test_br_common.py b/pycounter/test/test_br_common.py
index e45690a..e42e891 100644
--- a/pycounter/test/test_br_common.py
+++ b/pycounter/test/test_br_common.py
@@ -4,12 +4,12 @@
 
 def test_publisher(all_book_reports):
     for publication in all_book_reports:
-        assert publication.publisher == u"Megadodo Publications"
+        assert publication.publisher == "Megadodo Publications"
 
 
 def test_platform(all_book_reports):
     for publication in all_book_reports:
-        assert publication.platform == u"HHGTTG Online"
+        assert publication.platform == "HHGTTG Online"
 
 
 def test_stats(all_book_reports):
@@ -18,7 +18,7 @@ def test_stats(all_book_reports):
 
 
 def test_customer(all_book_reports):
-    assert all_book_reports.customer == u"University of Maximegalon"
+    assert all_book_reports.customer == "University of Maximegalon"
 
 
 def test_date_run(all_book_reports):
diff --git a/pycounter/test/test_classes.py b/pycounter/test/test_classes.py
index e6cd850..0a5df95 100644
--- a/pycounter/test/test_classes.py
+++ b/pycounter/test/test_classes.py
@@ -7,7 +7,7 @@
 
 def test_counter_journal():
     journal = report.CounterJournal()
-    assert journal.issn == u""
+    assert journal.issn == ""
 
 
 def test_report_gaps():
diff --git a/pycounter/test/test_db1.py b/pycounter/test/test_db1.py
index 5f87ec1..a55d104 100644
--- a/pycounter/test/test_db1.py
+++ b/pycounter/test/test_db1.py
@@ -17,7 +17,7 @@ def setUp(self):
         )
 
     def test_reportname(self):
-        self.assertEqual(self.report.report_type, u"DB1")
+        self.assertEqual(self.report.report_type, "DB1")
 
     def test_stats(self):
         publication = self.report.pubs[0]
@@ -38,4 +38,4 @@ def setUp(self):
         )
 
     def test_reportname(self):
-        self.assertEqual(self.report.report_type, u"DB1")
+        self.assertEqual(self.report.report_type, "DB1")
diff --git a/pycounter/test/test_db2.py b/pycounter/test/test_db2.py
index b480250..9594d53 100644
--- a/pycounter/test/test_db2.py
+++ b/pycounter/test/test_db2.py
@@ -17,7 +17,7 @@ def setUp(self):
         )
 
     def test_reportname(self):
-        self.assertEqual(self.report.report_type, u"DB2")
+        self.assertEqual(self.report.report_type, "DB2")
 
     def test_stats(self):
         publication = self.report.pubs[0]
diff --git a/pycounter/test/test_db_common.py b/pycounter/test/test_db_common.py
index fb30419..5df2f07 100644
--- a/pycounter/test/test_db_common.py
+++ b/pycounter/test/test_db_common.py
@@ -10,16 +10,16 @@ def test_version(db_report):
 
 def test_publisher(db_report):
     for publication in db_report:
-        assert publication.publisher == u"Megadodo Publications"
+        assert publication.publisher == "Megadodo Publications"
 
 
 def test_platform(db_report):
     for publication in db_report:
-        assert publication.platform == u"HHGTTG Online"
+        assert publication.platform == "HHGTTG Online"
 
 
 def test_customer(db_report):
-    assert db_report.customer == u"University of Maximegalon"
+    assert db_report.customer == "University of Maximegalon"
 
 
 def test_date_run(db_report):
diff --git a/pycounter/test/test_jr1_csv.py b/pycounter/test/test_jr1_csv.py
index d2685fe..4e7e7b6 100644
--- a/pycounter/test/test_jr1_csv.py
+++ b/pycounter/test/test_jr1_csv.py
@@ -24,11 +24,11 @@ def test_counter4_csv_data(csv_jr1_report_common_data, pub_number, expected):
 
 
 def test_metric(csv_jr1_report_std):
-    assert csv_jr1_report_std.metric == u"FT Article Requests"
+    assert csv_jr1_report_std.metric == "FT Article Requests"
 
 
 def test_customer(csv_jr1_report):
-    assert csv_jr1_report.customer == u"University of Maximegalon"
+    assert csv_jr1_report.customer == "University of Maximegalon"
 
 
 def test_date_run(csv_jr1_report):
@@ -43,7 +43,7 @@ def test_period(csv_jr1_report):
 
 
 def test_report_type(csv_jr1_report_std):
-    assert csv_jr1_report_std.report_type == u"JR1"
+    assert csv_jr1_report_std.report_type == "JR1"
 
 
 def test_ibsn(csv_jr1_r4_report):
@@ -121,7 +121,7 @@ def setUp(self):
         )
 
     def test_metric(self):
-        self.assertEqual(self.report.metric, u"Gold Open Access Article Requests")
+        self.assertEqual(self.report.metric, "Gold Open Access Article Requests")
 
 
 class ParseCounter4Bad(unittest.TestCase):
diff --git a/pycounter/test/test_jr1_xslx.py b/pycounter/test/test_jr1_xslx.py
index 59330f2..9f507ac 100644
--- a/pycounter/test/test_jr1_xslx.py
+++ b/pycounter/test/test_jr1_xslx.py
@@ -6,7 +6,7 @@
 
 
 def test_report_type(jr1_report_xlsx):
-    assert jr1_report_xlsx.report_type == u"JR1"
+    assert jr1_report_xlsx.report_type == "JR1"
 
 
 def test_report_version(jr1_report_xlsx):
@@ -15,14 +15,14 @@ def test_report_version(jr1_report_xlsx):
 
 def test_publisher(jr1_report_xlsx):
     assert all(  # pragma: no branch
-        publication.publisher == u"American Medical Association"
+        publication.publisher == "American Medical Association"
         for publication in jr1_report_xlsx
     )
 
 
 def test_platform(jr1_report_xlsx):
     for publication in jr1_report_xlsx:
-        assert publication.platform == u"Silverchair"
+        assert publication.platform == "Silverchair"
 
 
 @pytest.mark.parametrize(
diff --git a/pycounter/test/test_output_jr1.py b/pycounter/test/test_output_jr1.py
index 6fc99fb..a2ad1e0 100644
--- a/pycounter/test/test_output_jr1.py
+++ b/pycounter/test/test_output_jr1.py
@@ -11,29 +11,29 @@ def test_ordering_output():
     report = pycounter.report.CounterReport(
         report_type="JR1",
         report_version=4,
-        customer=u"Foo",
-        institutional_identifier=u"Bar",
+        customer="Foo",
+        institutional_identifier="Bar",
         period=(datetime.date(2016, 1, 1), datetime.date(2016, 1, 31)),
     )
     report.pubs.append(
         pycounter.report.CounterJournal(
             period=(datetime.date(2016, 1, 1), datetime.date(2016, 1, 31)),
             month_data=[(datetime.date(2016, 1, 1), 260)],
-            title=u"Fake Journal",
-            publisher=u"No one",
-            platform=u"Your imagination",
+            title="Fake Journal",
+            publisher="No one",
+            platform="Your imagination",
         )
     )
     report.pubs.append(
         pycounter.report.CounterJournal(
             period=(datetime.date(2016, 1, 1), datetime.date(2016, 1, 31)),
             month_data=[(datetime.date(2016, 1, 1), 62)],
-            title=u"Another Fake Journal",
-            publisher=u"No one",
-            platform=u"Your imagination",
+            title="Another Fake Journal",
+            publisher="No one",
+            platform="Your imagination",
         )
     )
     output_content = report.as_generic()
 
-    assert output_content[9][0] == u"Another Fake Journal"
-    assert output_content[10][0] == u"Fake Journal"
+    assert output_content[9][0] == "Another Fake Journal"
+    assert output_content[10][0] == "Fake Journal"
diff --git a/pycounter/test/test_pr1.py b/pycounter/test/test_pr1.py
index f4b8dd2..814aee3 100644
--- a/pycounter/test/test_pr1.py
+++ b/pycounter/test/test_pr1.py
@@ -17,7 +17,7 @@ def setUp(self):
         )
 
     def test_reportname(self):
-        self.assertEqual(self.report.report_type, u"PR1")
+        self.assertEqual(self.report.report_type, "PR1")
 
     def test_stats(self):
         publication = self.report.pubs[0]
diff --git a/pycounter/test/test_sushi.py b/pycounter/test/test_sushi.py
index 1572901..82b48b0 100644
--- a/pycounter/test/test_sushi.py
+++ b/pycounter/test/test_sushi.py
@@ -58,23 +58,23 @@ def test_report_version(sushi_report_all):
 
 
 def test_report_customer(sushi_report_with_customer):
-    assert sushi_report_with_customer.institutional_identifier == u"exampleLibrary"
+    assert sushi_report_with_customer.institutional_identifier == "exampleLibrary"
 
 
 def test_report_no_customer(sushi_report_no_customer):
-    assert sushi_report_no_customer.institutional_identifier == u""
+    assert sushi_report_no_customer.institutional_identifier == ""
 
 
 def test_report_type_jr1(sushi_report_jr1):
-    assert sushi_report_jr1.report_type == u"JR1"
+    assert sushi_report_jr1.report_type == "JR1"
 
 
 def test_data_jr1(sushi_report_jr1):
     publication = next(iter(sushi_report_jr1))
     assert publication.html_total == 6
     assert publication.pdf_total == 8
-    assert publication.doi == u"10.5555/12345678"
-    assert publication.proprietary_id == u"JFD"
+    assert publication.doi == "10.5555/12345678"
+    assert publication.proprietary_id == "JFD"
 
     data = [month[2] for month in publication]
 
@@ -83,7 +83,7 @@ def test_data_jr1(sushi_report_jr1):
 
 def test_title_jr1(sushi_report_jr1):
     publication = next(iter(sushi_report_jr1))
-    assert publication.title == u"Journal of fake data"
+    assert publication.title == "Journal of fake data"
 
 
 class TestConvertRawBook(unittest.TestCase):
@@ -95,19 +95,19 @@ def setUp(self):
             self.report = sushi.raw_to_full(datafile.read())
 
     def test_report(self):
-        self.assertEqual(self.report.report_type, u"BR1")
+        self.assertEqual(self.report.report_type, "BR1")
 
     def test_isbn(self):
         i_report = iter(self.report)
         publication = next(i_report)
-        self.assertEqual(publication.isbn, u"9780011234549")
+        self.assertEqual(publication.isbn, "9780011234549")
         next(i_report)
         pub3 = next(i_report)
-        self.assertEqual(pub3.isbn, u"9780011234540")
+        self.assertEqual(pub3.isbn, "9780011234540")
 
     def test_title(self):
         publication = next(iter(self.report))
-        self.assertEqual(publication.title, u"Fake data")
+        self.assertEqual(publication.title, "Fake data")
 
     def test_data(self):
         publication = next(iter(self.report))
@@ -116,7 +116,7 @@ def test_data(self):
 
     def test_proprietary(self):
         publication = next(iter(self.report))
-        self.assertEqual(publication.proprietary_id, u"FD")
+        self.assertEqual(publication.proprietary_id, "FD")
 
 
 class TestConvertRawDatabase(unittest.TestCase):
@@ -129,42 +129,42 @@ def setUp(self):
         self.databases = list(self.report)
 
     def test_report(self):
-        self.assertEqual(self.report.report_type, u"DB1")
+        self.assertEqual(self.report.report_type, "DB1")
 
     def test_platform(self):
         database = self.databases[0]
-        self.assertEqual(database.platform, u"ExamplePlatform")
+        self.assertEqual(database.platform, "ExamplePlatform")
 
     def test_publisher(self):
         database = self.databases[0]
-        self.assertEqual(database.publisher, u"ExamplePublisher")
+        self.assertEqual(database.publisher, "ExamplePublisher")
 
     def test_title(self):
         database = self.databases[0]
-        self.assertEqual(database.title, u"ExampleDatabase")
+        self.assertEqual(database.title, "ExampleDatabase")
 
     def test_search_reg(self):
         database = self.databases[0]
         data = [month[2] for month in database]
-        self.assertEqual(database.metric, u"Regular Searches")
+        self.assertEqual(database.metric, "Regular Searches")
         self.assertEqual(data[0], 5)
 
     def test_search_fed(self):
         database = self.databases[1]
         data = [month[2] for month in database]
-        self.assertEqual(database.metric, u"Searches-federated and automated")
+        self.assertEqual(database.metric, "Searches-federated and automated")
         self.assertEqual(data[0], 13)
 
     def test_result_click(self):
         database = self.databases[2]
         data = [month[2] for month in database]
-        self.assertEqual(database.metric, u"Result Clicks")
+        self.assertEqual(database.metric, "Result Clicks")
         self.assertEqual(data[0], 16)
 
     def test_record_view(self):
         database = self.databases[3]
         data = [month[2] for month in database]
-        self.assertEqual(database.metric, u"Record Views")
+        self.assertEqual(database.metric, "Record Views")
         self.assertEqual(data[0], 7)
 
 
@@ -187,13 +187,13 @@ def setUp(self):
     def test_january(self):
         database = self.databases[1]
         data = [month[2] for month in database]
-        self.assertEqual(database.metric, u"Searches-federated and automated")
+        self.assertEqual(database.metric, "Searches-federated and automated")
         self.assertEqual(data[0], 0)
 
     def test_record_view(self):
         database = self.databases[3]
         data = [month[2] for month in database]
-        self.assertEqual(database.metric, u"Record Views")
+        self.assertEqual(database.metric, "Record Views")
         self.assertEqual(data[0], 0)
 
 
@@ -211,7 +211,7 @@ def test_february(self):
         self.assertEqual(first_month_data[0], datetime.date(2013, 2, 1))
 
     def test_title(self):
-        self.assertEqual(self.publication.title, u"Journal of fake data")
+        self.assertEqual(self.publication.title, "Journal of fake data")
 
 
 class TestSushiRequest(unittest.TestCase):
@@ -226,7 +226,7 @@ def setUp(self):
             )
 
     def test_report(self):
-        self.assertEqual(self.report.report_type, u"JR1")
+        self.assertEqual(self.report.report_type, "JR1")
         self.assertEqual(self.report.report_version, 4)