From 012bf90ede987caa21f7758337f8b85ab622cbb2 Mon Sep 17 00:00:00 2001
From: StrikerRUS <nekit94-12@hotmail.com>
Date: Fri, 19 Jun 2020 02:01:10 +0300
Subject: [PATCH] drop string.Template from tests and migrate from format to
 f-strings

---
 tests/assemblers/test_lightgbm.py   |  3 ++-
 tests/assemblers/test_svm.py        |  1 +
 tests/assemblers/test_xgboost.py    |  3 ++-
 tests/e2e/executors/base.py         |  2 +-
 tests/e2e/executors/c.py            | 28 +++++++++++++---------------
 tests/e2e/executors/c_sharp.py      | 23 +++++++++++------------
 tests/e2e/executors/dart.py         | 15 +++++++--------
 tests/e2e/executors/go.py           | 23 ++++++++++-------------
 tests/e2e/executors/haskell.py      | 15 +++++++--------
 tests/e2e/executors/java.py         |  8 +++++---
 tests/e2e/executors/javascript.py   |  3 ++-
 tests/e2e/executors/php.py          | 23 +++++++++++------------
 tests/e2e/executors/powershell.py   | 19 +++++++++----------
 tests/e2e/executors/python.py       |  2 +-
 tests/e2e/executors/r.py            |  9 ++++-----
 tests/e2e/executors/ruby.py         | 11 +++++------
 tests/e2e/executors/visual_basic.py |  7 +++----
 tests/e2e/test_e2e.py               |  3 +--
 tests/test_cli.py                   |  2 +-
 tests/utils.py                      | 23 ++++++++++++-----------
 tools/generate_code_examples.py     |  2 +-
 21 files changed, 109 insertions(+), 116 deletions(-)

diff --git a/tests/assemblers/test_lightgbm.py b/tests/assemblers/test_lightgbm.py
index edb60677..49be06d2 100644
--- a/tests/assemblers/test_lightgbm.py
+++ b/tests/assemblers/test_lightgbm.py
@@ -1,7 +1,8 @@
 import lightgbm
 import numpy as np
-from tests import utils
+
 from m2cgen import assemblers, ast
+from tests import utils
 
 
 def test_binary_classification():
diff --git a/tests/assemblers/test_svm.py b/tests/assemblers/test_svm.py
index 86164490..6075be32 100644
--- a/tests/assemblers/test_svm.py
+++ b/tests/assemblers/test_svm.py
@@ -2,6 +2,7 @@
 import numpy as np
 from sklearn import svm
 from lightning.classification import KernelSVC
+
 from m2cgen import assemblers, ast
 from tests import utils
 
diff --git a/tests/assemblers/test_xgboost.py b/tests/assemblers/test_xgboost.py
index 67ba7cef..02a60d5c 100644
--- a/tests/assemblers/test_xgboost.py
+++ b/tests/assemblers/test_xgboost.py
@@ -1,8 +1,9 @@
 import xgboost
 import numpy as np
 import os
-from tests import utils
+
 from m2cgen import assemblers, ast
+from tests import utils
 
 
 def test_binary_classification():
diff --git a/tests/e2e/executors/base.py b/tests/e2e/executors/base.py
index adb62637..b7835d30 100644
--- a/tests/e2e/executors/base.py
+++ b/tests/e2e/executors/base.py
@@ -24,4 +24,4 @@ def prepare(self):
     @classmethod
     def prepare_global(cls, **kwargs):
         for key, value in kwargs.items():
-            setattr(cls, "_{}".format(key), value)
+            setattr(cls, f"_{key}", value)
diff --git a/tests/e2e/executors/c.py b/tests/e2e/executors/c.py
index 077f8929..0bc656fd 100644
--- a/tests/e2e/executors/c.py
+++ b/tests/e2e/executors/c.py
@@ -1,5 +1,4 @@
 import os
-import string
 import subprocess
 
 from m2cgen import interpreters, assemblers
@@ -10,19 +9,19 @@
 EXECUTOR_CODE_TPL = """
 #include <stdio.h>
 
-${model_code}
+{model_code}
 
 int main(int argc, char *argv[])
-{
+{{
     double input [argc-1];
-    for (int i = 1; i < argc; ++i) {
+    for (int i = 1; i < argc; ++i) {{
         sscanf(argv[i], "%lf", &input[i-1]);
-    }
+    }}
 
-    ${print_code}
+    {print_code}
 
     return 0;
-}
+}}
 """
 
 EXECUTE_AND_PRINT_SCALAR = """
@@ -30,12 +29,12 @@
 """
 
 EXECUTE_AND_PRINT_VECTOR_TPL = """
-    double result[${size}];
+    double result[{size}];
     score(input, result);
 
-    for (int i = 0; i < ${size}; ++i) {
+    for (int i = 0; i < {size}; ++i) {{
         printf("%f ", *(result+i));
-    }
+    }}
 """
 
 
@@ -61,18 +60,17 @@ def predict(self, X):
     def prepare(self):
 
         if self.model_ast.output_size > 1:
-            print_code = (
-                string.Template(EXECUTE_AND_PRINT_VECTOR_TPL).substitute(
-                    size=self.model_ast.output_size))
+            print_code = EXECUTE_AND_PRINT_VECTOR_TPL.format(
+                size=self.model_ast.output_size)
         else:
             print_code = EXECUTE_AND_PRINT_SCALAR
 
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             model_code=self.interpreter.interpret(self.model_ast),
             print_code=print_code)
 
         file_name = os.path.join(
-            self._resource_tmp_dir, "{}.c".format(self.model_name))
+            self._resource_tmp_dir, f"{self.model_name}.c")
 
         with open(file_name, "w") as f:
             f.write(executor_code)
diff --git a/tests/e2e/executors/c_sharp.py b/tests/e2e/executors/c_sharp.py
index c59fe667..c64269c7 100644
--- a/tests/e2e/executors/c_sharp.py
+++ b/tests/e2e/executors/c_sharp.py
@@ -1,5 +1,4 @@
 import os
-import string
 import subprocess
 
 from m2cgen import assemblers, interpreters
@@ -9,17 +8,17 @@
 EXECUTOR_CODE_TPL = """
 using System;
 
-namespace TestConsoleApp {
-    class Program {
-        static void Main(string[] args) {
+namespace TestConsoleApp {{
+    class Program {{
+        static void Main(string[] args) {{
             double[] input_ = new double[args.Length];
-            for(int i = 0; i < input_.Length; ++i) {
+            for(int i = 0; i < input_.Length; ++i) {{
                 input_[i] = double.Parse(args[i]);
-            }
-            ${print_code}
-        }
-    }
-}
+            }}
+            {print_code}
+        }}
+    }}
+}}
 """
 
 EXECUTE_AND_PRINT_SCALAR = """
@@ -74,7 +73,7 @@ def prepare(self):
             print_code = EXECUTE_AND_PRINT_VECTOR
         else:
             print_code = EXECUTE_AND_PRINT_SCALAR
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             print_code=print_code)
         model_code = self.interpreter.interpret(self.model_ast)
 
@@ -88,6 +87,6 @@ def prepare(self):
         subprocess.call([self._dotnet,
                          "build",
                          os.path.join(self._global_tmp_dir,
-                                      "{}.csproj".format(self.project_name)),
+                                      f"{self.project_name}.csproj"),
                          "--output",
                          self.target_exec_dir])
diff --git a/tests/e2e/executors/dart.py b/tests/e2e/executors/dart.py
index e17e8baf..64c489da 100644
--- a/tests/e2e/executors/dart.py
+++ b/tests/e2e/executors/dart.py
@@ -1,17 +1,16 @@
 import os
-import string
 
 from m2cgen import assemblers, interpreters
 from tests import utils
 from tests.e2e.executors import base
 
 EXECUTOR_CODE_TPL = """
-${model_code}
+{model_code}
 
-void main(List<String> args) {
+void main(List<String> args) {{
     List<double> input_ = args.map((x) => double.parse(x)).toList();
-    ${print_code}
-}
+    {print_code}
+}}
 """
 
 EXECUTE_AND_PRINT_SCALAR = """
@@ -40,7 +39,7 @@ def __init__(self, model):
 
     def predict(self, X):
         file_name = os.path.join(self._resource_tmp_dir,
-                                 "{}.dart".format(self.executor_name))
+                                 f"{self.executor_name}.dart")
         exec_args = [self._dart,
                      file_name,
                      *map(str, X)]
@@ -53,11 +52,11 @@ def prepare(self):
             print_code = EXECUTE_AND_PRINT_SCALAR
 
         model_code = self.interpreter.interpret(self.model_ast)
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             model_code=model_code,
             print_code=print_code)
 
         executor_file_name = os.path.join(
-            self._resource_tmp_dir, "{}.dart".format(self.executor_name))
+            self._resource_tmp_dir, f"{self.executor_name}.dart")
         with open(executor_file_name, "w") as f:
             f.write(executor_code)
diff --git a/tests/e2e/executors/go.py b/tests/e2e/executors/go.py
index 2a2a2b13..1d5b99c4 100644
--- a/tests/e2e/executors/go.py
+++ b/tests/e2e/executors/go.py
@@ -1,5 +1,4 @@
 import os
-import string
 import subprocess
 
 from m2cgen import assemblers, interpreters
@@ -15,24 +14,24 @@
     "strconv"
 )
 
-${model_code}
+{model_code}
 
-func main() {
+func main() {{
     input := make([]float64, 0, len(os.Args)-1)
-    for _, s := range os.Args[1:] {
+    for _, s := range os.Args[1:] {{
         f, _ := strconv.ParseFloat(s, 64)
         input = append(input, f)
-    }
+    }}
 
-    ${print_code}
-}
+    {print_code}
+}}
 """
 
 EXECUTE_AND_PRINT_SCALAR = """
     fmt.Printf("%f\\n", score(input))
 """
 
-EXECUTE_AND_PRINT_VECTOR_TPL = """
+EXECUTE_AND_PRINT_VECTOR = """
     result := score(input)
 
     for _, v := range result {
@@ -62,18 +61,16 @@ def predict(self, X):
     def prepare(self):
 
         if self.model_ast.output_size > 1:
-            print_code = (
-                string.Template(EXECUTE_AND_PRINT_VECTOR_TPL).substitute(
-                    size=self.model_ast.output_size))
+            print_code = EXECUTE_AND_PRINT_VECTOR
         else:
             print_code = EXECUTE_AND_PRINT_SCALAR
 
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             model_code=self.interpreter.interpret(self.model_ast),
             print_code=print_code)
 
         file_name = os.path.join(
-            self._resource_tmp_dir, "{}.go".format(self.model_name))
+            self._resource_tmp_dir, f"{self.model_name}.go")
 
         with open(file_name, "w") as f:
             f.write(executor_code)
diff --git a/tests/e2e/executors/haskell.py b/tests/e2e/executors/haskell.py
index 8f465100..022901cf 100644
--- a/tests/e2e/executors/haskell.py
+++ b/tests/e2e/executors/haskell.py
@@ -1,5 +1,4 @@
 import os
-import string
 import subprocess
 
 from m2cgen import assemblers, interpreters
@@ -7,15 +6,15 @@
 from tests.e2e.executors import base
 
 EXECUTOR_CODE_TPL = """
-module ${executor_name} where
+module {executor_name} where
 import System.Environment (getArgs)
-import ${model_name}
+import {model_name}
 
 main = do
     args <- getArgs
     let inputArray = [read i::Double | i <- args]
     let res = score inputArray
-    ${print_code}
+    {print_code}
 """
 
 PRINT_SCALAR = "print res"
@@ -48,23 +47,23 @@ def prepare(self):
             print_code = PRINT_VECTOR
         else:
             print_code = PRINT_SCALAR
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             executor_name=self.executor_name,
             model_name=self.model_name,
             print_code=print_code)
         model_code = self.interpreter.interpret(self.model_ast)
 
         executor_file_name = os.path.join(
-            self._resource_tmp_dir, "{}.hs".format(self.executor_name))
+            self._resource_tmp_dir, f"{self.executor_name}.hs")
         model_file_name = os.path.join(
-            self._resource_tmp_dir, "{}.hs".format(self.model_name))
+            self._resource_tmp_dir, f"{self.model_name}.hs")
         with open(executor_file_name, "w") as f:
             f.write(executor_code)
         with open(model_file_name, "w") as f:
             f.write(model_code)
 
         exec_args = [self._ghc, executor_file_name,
-                     "-i{}".format(self._resource_tmp_dir),
+                     f"-i{self._resource_tmp_dir}",
                      "-o", os.path.join(self._resource_tmp_dir,
                                         self.executor_name)]
         subprocess.call(exec_args)
diff --git a/tests/e2e/executors/java.py b/tests/e2e/executors/java.py
index 357e2c0a..e1222599 100644
--- a/tests/e2e/executors/java.py
+++ b/tests/e2e/executors/java.py
@@ -31,7 +31,7 @@ def prepare(self):
         # Create files generated by exporter in the temp dir.
         code = m2c.export_to_java(self.model, class_name=self.class_name)
         code_file_name = os.path.join(self._resource_tmp_dir,
-                                      "{}.java".format(self.class_name))
+                                      f"{self.class_name}.java")
 
         with open(code_file_name, "w") as f:
             f.write(code)
@@ -42,6 +42,8 @@ def prepare(self):
                     self._resource_tmp_dir)
 
         # Compile all files together.
-        exec_args = [self._javac_bin, code_file_name] + (
-            [os.path.join(self._resource_tmp_dir, "Executor.java")])
+        exec_args = [
+            self._javac_bin,
+            code_file_name,
+            os.path.join(self._resource_tmp_dir, "Executor.java")]
         subprocess.call(exec_args)
diff --git a/tests/e2e/executors/javascript.py b/tests/e2e/executors/javascript.py
index b58dabe4..5d387fc0 100644
--- a/tests/e2e/executors/javascript.py
+++ b/tests/e2e/executors/javascript.py
@@ -1,5 +1,6 @@
 import os
 from py_mini_racer import py_mini_racer
+
 import m2cgen as m2c
 from tests.e2e.executors import base
 
@@ -15,7 +16,7 @@ def predict(self, X):
         with open(file_name, 'r') as myfile:
             code = myfile.read()
 
-        caller = "score([" + ",".join(map(str, X)) + "]);\n"
+        caller = f"score([{','.join(map(str, X))}]);\n"
 
         ctx = py_mini_racer.MiniRacer()
         result = ctx.eval(caller + code)
diff --git a/tests/e2e/executors/php.py b/tests/e2e/executors/php.py
index 742a430e..9b56026e 100644
--- a/tests/e2e/executors/php.py
+++ b/tests/e2e/executors/php.py
@@ -1,5 +1,4 @@
 import os
-import string
 
 from m2cgen import assemblers, interpreters
 from tests import utils
@@ -7,16 +6,16 @@
 
 EXECUTOR_CODE_TPL = """
 <?php
-$$inputArray = array();
-for ($$i = 1; $$i < $$argc; ++$$i) {
-    $$inputArray[] = floatval($$argv[$$i]);
-}
+$inputArray = array();
+for ($i = 1; $i < $argc; ++$i) {{
+    $inputArray[] = floatval($argv[$i]);
+}}
 
-require '${model_file}.php';
+require '{model_file}.php';
 
-$$res = score($$inputArray);
+$res = score($inputArray);
 
-${print_code}
+{print_code}
 """
 
 PRINT_SCALAR = """
@@ -44,7 +43,7 @@ def __init__(self, model):
 
     def predict(self, X):
         file_name = os.path.join(self._resource_tmp_dir,
-                                 "{}.php".format(self.executor_name))
+                                 f"{self.executor_name}.php")
         exec_args = [self._php,
                      "-f",
                      file_name,
@@ -56,15 +55,15 @@ def prepare(self):
             print_code = PRINT_VECTOR
         else:
             print_code = PRINT_SCALAR
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             model_file=self.model_name,
             print_code=print_code)
         model_code = self.interpreter.interpret(self.model_ast)
 
         executor_file_name = os.path.join(
-            self._resource_tmp_dir, "{}.php".format(self.executor_name))
+            self._resource_tmp_dir, f"{self.executor_name}.php")
         model_file_name = os.path.join(
-            self._resource_tmp_dir, "{}.php".format(self.model_name))
+            self._resource_tmp_dir, f"{self.model_name}.php")
         with open(executor_file_name, "w") as f:
             f.write(executor_code)
         with open(model_file_name, "w") as f:
diff --git a/tests/e2e/executors/powershell.py b/tests/e2e/executors/powershell.py
index a7b2d8fe..a3eafca7 100644
--- a/tests/e2e/executors/powershell.py
+++ b/tests/e2e/executors/powershell.py
@@ -1,6 +1,5 @@
 import os
 import platform
-import string
 
 from m2cgen import assemblers, interpreters
 from tests import utils
@@ -8,15 +7,15 @@
 
 EXECUTOR_CODE_TPL = """
 param (
-    $$InputArray
+    $InputArray
 )
-$$InputArray = [double[]]($$InputArray -Split ',')
+$InputArray = [double[]]($InputArray -Split ',')
 
-${model_code}
+{model_code}
 
-Score $$InputArray | ForEach-Object {
-  Write-Host -NoNewline "$$_ "
-}
+Score $InputArray | ForEach-Object {{
+  Write-Host -NoNewline "$_ "
+}}
 """
 
 
@@ -36,7 +35,7 @@ def __init__(self, model):
 
     def predict(self, X):
         file_name = os.path.join(self._resource_tmp_dir,
-                                 "{}.ps1".format(self.model_name))
+                                 f"{self.model_name}.ps1")
         exec_args = [self._powershell,
                      "-File",
                      file_name,
@@ -45,10 +44,10 @@ def predict(self, X):
         return utils.predict_from_commandline(exec_args)
 
     def prepare(self):
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             model_code=self.interpreter.interpret(self.model_ast))
 
         file_name = os.path.join(
-            self._resource_tmp_dir, "{}.ps1".format(self.model_name))
+            self._resource_tmp_dir, f"{self.model_name}.ps1")
         with open(file_name, "w") as f:
             f.write(executor_code)
diff --git a/tests/e2e/executors/python.py b/tests/e2e/executors/python.py
index 0afc5b69..668720d3 100644
--- a/tests/e2e/executors/python.py
+++ b/tests/e2e/executors/python.py
@@ -20,7 +20,7 @@ def predict(self, X):
         sys.path.append(parent_dir)
 
         try:
-            score = importlib.import_module("{}.model".format(package)).score
+            score = importlib.import_module(f"{package}.model").score
         finally:
             sys.path.pop()
 
diff --git a/tests/e2e/executors/r.py b/tests/e2e/executors/r.py
index 796555b8..f1494209 100644
--- a/tests/e2e/executors/r.py
+++ b/tests/e2e/executors/r.py
@@ -1,5 +1,4 @@
 import os
-import string
 
 from m2cgen import assemblers, interpreters
 from tests import utils
@@ -9,7 +8,7 @@
 args = commandArgs(trailingOnly = TRUE)
 input_array <- as.double(args)
 
-${model_code}
+{model_code}
 
 res <- score(input_array)
 cat(res, sep = " ")
@@ -31,7 +30,7 @@ def __init__(self, model):
 
     def predict(self, X):
         file_name = os.path.join(self._resource_tmp_dir,
-                                 "{}.r".format(self.model_name))
+                                 f"{self.model_name}.r")
         exec_args = [self._r,
                      "--vanilla",
                      file_name,
@@ -39,10 +38,10 @@ def predict(self, X):
         return utils.predict_from_commandline(exec_args)
 
     def prepare(self):
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             model_code=self.interpreter.interpret(self.model_ast))
 
         file_name = os.path.join(
-            self._resource_tmp_dir, "{}.r".format(self.model_name))
+            self._resource_tmp_dir, f"{self.model_name}.r")
         with open(file_name, "w") as f:
             f.write(executor_code)
diff --git a/tests/e2e/executors/ruby.py b/tests/e2e/executors/ruby.py
index f0d3c571..3615e2af 100644
--- a/tests/e2e/executors/ruby.py
+++ b/tests/e2e/executors/ruby.py
@@ -1,5 +1,4 @@
 import os
-import string
 
 from m2cgen import assemblers, interpreters
 from tests import utils
@@ -8,11 +7,11 @@
 EXECUTOR_CODE_TPL = """
 input_array = ARGV.map(&:to_f)
 
-${model_code}
+{model_code}
 
 res = score(input_array)
 
-${print_code}
+{print_code}
 """
 
 PRINT_SCALAR = """
@@ -38,7 +37,7 @@ def __init__(self, model):
 
     def predict(self, X):
         file_name = os.path.join(self._resource_tmp_dir,
-                                 "{}.rb".format(self.model_name))
+                                 f"{self.model_name}.rb")
         exec_args = [self._ruby, file_name, *map(str, X)]
         return utils.predict_from_commandline(exec_args)
 
@@ -47,11 +46,11 @@ def prepare(self):
             print_code = PRINT_VECTOR
         else:
             print_code = PRINT_SCALAR
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             model_code=self.interpreter.interpret(self.model_ast),
             print_code=print_code)
 
         file_name = os.path.join(
-            self._resource_tmp_dir, "{}.rb".format(self.model_name))
+            self._resource_tmp_dir, f"{self.model_name}.rb")
         with open(file_name, "w") as f:
             f.write(executor_code)
diff --git a/tests/e2e/executors/visual_basic.py b/tests/e2e/executors/visual_basic.py
index 8c7c1f72..89a88c28 100644
--- a/tests/e2e/executors/visual_basic.py
+++ b/tests/e2e/executors/visual_basic.py
@@ -1,5 +1,4 @@
 import os
-import string
 import subprocess
 
 from m2cgen import assemblers, interpreters
@@ -16,7 +15,7 @@
         For i = LBound(cmdArgs) To UBound(cmdArgs)
             inputVector(i) = CDbl(cmdArgs(i))
         Next i
-        ${print_code}
+        {print_code}
     End Sub
 
 End Module
@@ -76,7 +75,7 @@ def prepare(self):
             print_code = EXECUTE_AND_PRINT_VECTOR
         else:
             print_code = EXECUTE_AND_PRINT_SCALAR
-        executor_code = string.Template(EXECUTOR_CODE_TPL).substitute(
+        executor_code = EXECUTOR_CODE_TPL.format(
             print_code=print_code)
         model_code = self.interpreter.interpret(self.model_ast)
 
@@ -90,6 +89,6 @@ def prepare(self):
         subprocess.call([self._dotnet,
                          "build",
                          os.path.join(self._global_tmp_dir,
-                                      "{}.vbproj".format(self.project_name)),
+                                      f"{self.project_name}.vbproj"),
                          "--output",
                          self.target_exec_dir])
diff --git a/tests/e2e/test_e2e.py b/tests/e2e/test_e2e.py
index 53e8f19d..acb4864e 100644
--- a/tests/e2e/test_e2e.py
+++ b/tests/e2e/test_e2e.py
@@ -524,7 +524,6 @@ def test_e2e(estimator, executor_cls, model_trainer,
     with executor.prepare_then_cleanup():
         for idx in idxs_to_test:
             y_pred_executed = executor.predict(X_test[idx])
-            print("expected={}, actual={}".format(y_pred_true[idx],
-                                                  y_pred_executed))
+            print(f"expected={y_pred_true[idx]}, actual={y_pred_executed}")
             res = np.isclose(y_pred_true[idx], y_pred_executed, atol=ATOL)
             assert res if isinstance(res, bool) else res.all()
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 9bb615c9..dc145030 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -143,7 +143,7 @@ def test_namespace():
 
     generated_code = cli.generate_code(mock_args).strip()
 
-    assert generated_code.find("namespace Tests.ML {") != -1
+    assert "namespace Tests.ML {" in generated_code
 
 
 def test_unsupported_args_are_ignored():
diff --git a/tests/utils.py b/tests/utils.py
index d92441ad..a5c4439e 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -113,7 +113,7 @@ def __init__(self, dataset_name, test_fraction):
 
     @classmethod
     def get_instance(cls, dataset_name, test_fraction=0.02):
-        key = dataset_name + " {}".format(test_fraction)
+        key = f"{dataset_name} {test_fraction}"
         if key not in cls._class_instances:
             cls._class_instances[key] = ModelTrainer(
                 dataset_name, test_fraction)
@@ -153,13 +153,12 @@ def cmp_exprs(left, right):
             comp_res = np.isclose(left, right)
         else:
             comp_res = left == right
-        assert comp_res, str(left) + " != " + str(right)
+        assert comp_res, f"{str(left)} != {str(right)}"
         return True
 
     if isinstance(left, ast.Expr) and isinstance(right, ast.Expr):
         assert isinstance(left, type(right)), (
-            "Expected instance of {}, received {}".format(
-                type(right), type(left)))
+            f"Expected instance of {type(right)}, received {type(left)}")
 
         # Only compare attributes which don't start with __
         attrs_to_compare = filter(
@@ -216,9 +215,10 @@ def tmp_dir():
 
 
 def verify_python_model_is_expected(model_code, input, expected_output):
-    input_str = "[" + ", ".join(map(str, input)) + "]"
-    code = model_code + """
-result = score({})""".format(input_str)
+    input_str = f"[{', '.join(map(str, input))}]"
+    code = f"""
+{model_code}
+result = score({input_str})"""
 
     context = {}
     exec(code, context)
@@ -231,8 +231,9 @@ def predict_from_commandline(exec_args):
                               stderr=subprocess.PIPE)
     stdout, stderr = result.communicate()
     if result.returncode != 0:
-        raise Exception("bad exit code ({}) stderr: {}".format(
-                        result.returncode, stderr.decode("utf-8")))
+        raise Exception(
+            f"Bad exit code ({result.returncode}), "
+            f"stderr:\n{stderr.decode('utf-8')}")
 
     items = stdout.decode("utf-8").strip().split(" ")
 
@@ -261,8 +262,8 @@ def cartesian_e2e_params(executors_with_marks, models_with_trainers_with_marks,
 
         # We use custom id since pytest for some reason can't show name of
         # the model in the automatic id. Which sucks.
-        ids.append("{} - {} - {}".format(
-            _get_full_model_name(model), executor_mark.name, trainer.name))
+        ids.append(f"{_get_full_model_name(model)} - "
+                   f"{executor_mark.name} - {trainer.name}")
 
         result_params.append(pytest.param(
             model, executor, trainer, marks=[executor_mark, trainer_mark],
diff --git a/tools/generate_code_examples.py b/tools/generate_code_examples.py
index 0bcee1db..fb663ff8 100644
--- a/tools/generate_code_examples.py
+++ b/tools/generate_code_examples.py
@@ -128,7 +128,7 @@
         folder = os.path.join(export_folder, language, mtype)
         os.makedirs(folder, exist_ok=True)
 
-        model_filename = "{}.{}".format(mname, file_ext)
+        model_filename = f"{mname}.{file_ext}"
         model_path = os.path.join(folder, model_filename)
 
         with open(model_path, "w") as f: