From 6b5152ae131ea2bd15f6c998de223b72b0c9e65d Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Sat, 13 Apr 2019 18:58:38 +0300
Subject: [PATCH 01/14] Sanity tests for loop unrolling

---
 testing/test_assertrewrite.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/testing/test_assertrewrite.py b/testing/test_assertrewrite.py
index 72bfbcc55..c22ae7c6e 100644
--- a/testing/test_assertrewrite.py
+++ b/testing/test_assertrewrite.py
@@ -656,6 +656,12 @@ class TestAssertionRewrite(object):
         else:
             assert lines == ["assert 0 == 1\n +  where 1 = \\n{ \\n~ \\n}.a"]
 
+    def test_all_unroll(self):
+        def f():
+            assert all(x == 1 for x in range(10))
+
+        assert "0 != 1" in getmsg(f)
+
     def test_custom_repr_non_ascii(self):
         def f():
             class A(object):

From 765f75a8f1d38413fa85ae51f61e6be969aac9d5 Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Sat, 13 Apr 2019 19:13:29 +0300
Subject: [PATCH 02/14] Replace asserts of `any` with an assert in a for

---
 src/_pytest/assertion/rewrite.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index 18506d2e1..68ff2b3ef 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -964,6 +964,8 @@ warn_explicit(
         """
         visit `ast.Call` nodes on Python3.5 and after
         """
+        if call.func.id == "all":
+            return self.visit_all(call)
         new_func, func_expl = self.visit(call.func)
         arg_expls = []
         new_args = []
@@ -987,6 +989,22 @@ warn_explicit(
         outer_expl = "%s\n{%s = %s\n}" % (res_expl, res_expl, expl)
         return res, outer_expl
 
+    def visit_all(self, call):
+        """Special rewrite for the builtin all function, see #5602"""
+        if not isinstance(call.args[0], ast.GeneratorExp):
+            return
+        gen_exp = call.args[0]
+        for_loop = ast.For(
+            iter=gen_exp.generators[0].iter,
+            target=gen_exp.generators[0].target,
+            body=[
+                self.visit(ast.Assert(test=gen_exp.elt, lineno=1, msg="", col_offset=1))
+            ],
+        )
+        ast.fix_missing_locations(for_loop)
+        for_loop = ast.copy_location(for_loop, call)
+        return for_loop, ""
+
     def visit_Starred(self, starred):
         # From Python 3.5, a Starred node can appear in a function call
         res, expl = self.visit(starred.value)

From 470e686a70df788ddc76ed45607f7cea1e85ec71 Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Sat, 13 Apr 2019 20:11:11 +0300
Subject: [PATCH 03/14] Rewrite unrolled assertion with a new
 rewriter,correctly append the unrolled for loop

---
 src/_pytest/assertion/rewrite.py | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index 68ff2b3ef..adf252009 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -994,16 +994,21 @@ warn_explicit(
         if not isinstance(call.args[0], ast.GeneratorExp):
             return
         gen_exp = call.args[0]
+        assertion_module = ast.Module(
+            body=[ast.Assert(test=gen_exp.elt, lineno=1, msg="", col_offset=1)]
+        )
+        AssertionRewriter(None, None).run(assertion_module)
         for_loop = ast.For(
             iter=gen_exp.generators[0].iter,
             target=gen_exp.generators[0].target,
-            body=[
-                self.visit(ast.Assert(test=gen_exp.elt, lineno=1, msg="", col_offset=1))
-            ],
+            body=assertion_module.body,
+            orelse=[],
         )
-        ast.fix_missing_locations(for_loop)
-        for_loop = ast.copy_location(for_loop, call)
-        return for_loop, ""
+        self.statements.append(for_loop)
+        return (
+            ast.Num(n=1),
+            "",
+        )  # Return an empty expression, all the asserts are in the for_loop
 
     def visit_Starred(self, starred):
         # From Python 3.5, a Starred node can appear in a function call

From ddbe733666d56b7c997bd901071f1608a0a90873 Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Sat, 13 Apr 2019 20:57:05 +0300
Subject: [PATCH 04/14] Add changelog entry for 5062

---
 changelog/5062.feature.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog/5062.feature.rst

diff --git a/changelog/5062.feature.rst b/changelog/5062.feature.rst
new file mode 100644
index 000000000..e311d161d
--- /dev/null
+++ b/changelog/5062.feature.rst
@@ -0,0 +1 @@
+Unroll calls to ``all`` to full for-loops for better failure messages, especially when using Generator Expressions.

From a0dbf2ab995780140ce335fb96e0f797c661764b Mon Sep 17 00:00:00 2001
From: danielx123 <danielx@umich.edu>
Date: Mon, 22 Apr 2019 17:58:07 -0400
Subject: [PATCH 05/14] Adding test cases for unrolling an iterable #5062

---
 testing/test_assertrewrite.py | 47 +++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/testing/test_assertrewrite.py b/testing/test_assertrewrite.py
index c22ae7c6e..8add65e0a 100644
--- a/testing/test_assertrewrite.py
+++ b/testing/test_assertrewrite.py
@@ -677,6 +677,53 @@ class TestAssertionRewrite(object):
         assert "UnicodeDecodeError" not in msg
         assert "UnicodeEncodeError" not in msg
 
+    def test_generator(self, testdir):
+        testdir.makepyfile(
+            """
+            def check_even(num):
+                if num % 2 == 0:
+                    return True
+                return False
+
+            def test_generator():
+                odd_list = list(range(1,9,2))
+                assert all(check_even(num) for num in odd_list)"""
+        )
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines(["*assert False*", "*where False = check_even(1)*"])
+
+    def test_list_comprehension(self, testdir):
+        testdir.makepyfile(
+            """
+            def check_even(num):
+                if num % 2 == 0:
+                    return True
+                return False
+
+            def test_list_comprehension():
+                odd_list = list(range(1,9,2))
+                assert all([check_even(num) for num in odd_list])"""
+        )
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines(["*assert False*", "*where False = check_even(1)*"])
+
+    def test_for_loop(self, testdir):
+        testdir.makepyfile(
+            """
+            def check_even(num):
+                if num % 2 == 0:
+                    return True
+                return False
+
+            def test_for_loop():
+                odd_list = list(range(1,9,2))
+                for num in odd_list:
+                    assert check_even(num)
+        """
+        )
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines(["*assert False*", "*where False = check_even(1)*"])
+
 
 class TestRewriteOnImport(object):
     def test_pycache_is_a_file(self, testdir):

From 0996f3dbc54d5b0d096e7341cb6718ffd16da100 Mon Sep 17 00:00:00 2001
From: danielx123 <danielx@umich.edu>
Date: Mon, 22 Apr 2019 18:23:51 -0400
Subject: [PATCH 06/14] Displaying pip list command's packages and versions
 #5062

---
 src/_pytest/terminal.py  | 6 ++++++
 testing/test_terminal.py | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/src/_pytest/terminal.py b/src/_pytest/terminal.py
index 2d7132259..98cbaa571 100644
--- a/src/_pytest/terminal.py
+++ b/src/_pytest/terminal.py
@@ -9,6 +9,7 @@ from __future__ import print_function
 import argparse
 import collections
 import platform
+import subprocess
 import sys
 import time
 from functools import partial
@@ -581,6 +582,11 @@ class TerminalReporter(object):
         ):
             msg += " -- " + str(sys.executable)
         self.write_line(msg)
+        pipe = subprocess.Popen("pip list", shell=True, stdout=subprocess.PIPE).stdout
+        package_msg = pipe.read()
+        package_msg = package_msg[:-2]
+        if package_msg:
+            self.write_line(package_msg)
         lines = self.config.hook.pytest_report_header(
             config=self.config, startdir=self.startdir
         )
diff --git a/testing/test_terminal.py b/testing/test_terminal.py
index feacc242d..bfa928d74 100644
--- a/testing/test_terminal.py
+++ b/testing/test_terminal.py
@@ -279,6 +279,15 @@ class TestTerminal(object):
         tr.rewrite("hey", erase=True)
         assert f.getvalue() == "hello" + "\r" + "hey" + (6 * " ")
 
+    def test_packages_display(self, testdir):
+        testdir.makepyfile(
+            """
+            def test_pass(num):
+                assert 1 == 1"""
+        )
+        result = testdir.runpytest()
+        result.stdout.fnmatch_lines(["*Package*", "*Version*"])
+
 
 class TestCollectonly(object):
     def test_collectonly_basic(self, testdir):

From c607697400affcc0e50e51baa329aec81ba3cf7b Mon Sep 17 00:00:00 2001
From: danielx123 <danielx@umich.edu>
Date: Mon, 22 Apr 2019 21:29:08 -0400
Subject: [PATCH 07/14] Fixed test case

---
 testing/test_terminal.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/testing/test_terminal.py b/testing/test_terminal.py
index bfa928d74..0b57114e5 100644
--- a/testing/test_terminal.py
+++ b/testing/test_terminal.py
@@ -286,7 +286,7 @@ class TestTerminal(object):
                 assert 1 == 1"""
         )
         result = testdir.runpytest()
-        result.stdout.fnmatch_lines(["*Package*", "*Version*"])
+        result.stdout.fnmatch_lines(["*Package        Version              *"])
 
 
 class TestCollectonly(object):

From ecd2de25a122cd79f2e9b37b267fe883272383c6 Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Thu, 9 May 2019 17:39:24 +0300
Subject: [PATCH 08/14] Revert "Displaying pip list command's packages and
 versions #5062"

This reverts commit 043fdb7c4065e5eb54f3fb5776077bb8fd651ce6.
These tests were part of the PR #5155 but weren't relevant to #5602
---
 src/_pytest/terminal.py  | 6 ------
 testing/test_terminal.py | 9 ---------
 2 files changed, 15 deletions(-)

diff --git a/src/_pytest/terminal.py b/src/_pytest/terminal.py
index 98cbaa571..2d7132259 100644
--- a/src/_pytest/terminal.py
+++ b/src/_pytest/terminal.py
@@ -9,7 +9,6 @@ from __future__ import print_function
 import argparse
 import collections
 import platform
-import subprocess
 import sys
 import time
 from functools import partial
@@ -582,11 +581,6 @@ class TerminalReporter(object):
         ):
             msg += " -- " + str(sys.executable)
         self.write_line(msg)
-        pipe = subprocess.Popen("pip list", shell=True, stdout=subprocess.PIPE).stdout
-        package_msg = pipe.read()
-        package_msg = package_msg[:-2]
-        if package_msg:
-            self.write_line(package_msg)
         lines = self.config.hook.pytest_report_header(
             config=self.config, startdir=self.startdir
         )
diff --git a/testing/test_terminal.py b/testing/test_terminal.py
index 0b57114e5..feacc242d 100644
--- a/testing/test_terminal.py
+++ b/testing/test_terminal.py
@@ -279,15 +279,6 @@ class TestTerminal(object):
         tr.rewrite("hey", erase=True)
         assert f.getvalue() == "hello" + "\r" + "hey" + (6 * " ")
 
-    def test_packages_display(self, testdir):
-        testdir.makepyfile(
-            """
-            def test_pass(num):
-                assert 1 == 1"""
-        )
-        result = testdir.runpytest()
-        result.stdout.fnmatch_lines(["*Package        Version              *"])
-
 
 class TestCollectonly(object):
     def test_collectonly_basic(self, testdir):

From e37ff3042e711dd930ed8cd315b3b93340546a25 Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Thu, 9 May 2019 17:50:41 +0300
Subject: [PATCH 09/14] Check calls to all only if it's a name and not an
 attribute

---
 src/_pytest/assertion/rewrite.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index adf252009..0a3713285 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -964,7 +964,7 @@ warn_explicit(
         """
         visit `ast.Call` nodes on Python3.5 and after
         """
-        if call.func.id == "all":
+        if isinstance(call.func, ast.Name) and call.func.id == "all":
             return self.visit_all(call)
         new_func, func_expl = self.visit(call.func)
         arg_expls = []

From 437d6452c1a37ef1412adb3fd79bc844f9d05c3a Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Thu, 9 May 2019 18:51:03 +0300
Subject: [PATCH 10/14] Expand list comprehensions as well

---
 src/_pytest/assertion/rewrite.py | 4 ++--
 testing/test_assertrewrite.py    | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index 0a3713285..0e988a8f4 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -991,13 +991,13 @@ warn_explicit(
 
     def visit_all(self, call):
         """Special rewrite for the builtin all function, see #5602"""
-        if not isinstance(call.args[0], ast.GeneratorExp):
+        if not isinstance(call.args[0], (ast.GeneratorExp, ast.ListComp)):
             return
         gen_exp = call.args[0]
         assertion_module = ast.Module(
             body=[ast.Assert(test=gen_exp.elt, lineno=1, msg="", col_offset=1)]
         )
-        AssertionRewriter(None, None).run(assertion_module)
+        AssertionRewriter(module_path=None, config=None).run(assertion_module)
         for_loop = ast.For(
             iter=gen_exp.generators[0].iter,
             target=gen_exp.generators[0].target,
diff --git a/testing/test_assertrewrite.py b/testing/test_assertrewrite.py
index 8add65e0a..c453fe57d 100644
--- a/testing/test_assertrewrite.py
+++ b/testing/test_assertrewrite.py
@@ -677,7 +677,7 @@ class TestAssertionRewrite(object):
         assert "UnicodeDecodeError" not in msg
         assert "UnicodeEncodeError" not in msg
 
-    def test_generator(self, testdir):
+    def test_unroll_generator(self, testdir):
         testdir.makepyfile(
             """
             def check_even(num):
@@ -692,7 +692,7 @@ class TestAssertionRewrite(object):
         result = testdir.runpytest()
         result.stdout.fnmatch_lines(["*assert False*", "*where False = check_even(1)*"])
 
-    def test_list_comprehension(self, testdir):
+    def test_unroll_list_comprehension(self, testdir):
         testdir.makepyfile(
             """
             def check_even(num):

From 852fb6a4ae93c68bd03f36ca4daf7e9642d8e2d2 Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Thu, 9 May 2019 19:02:50 +0300
Subject: [PATCH 11/14] Change basic test case to be consistent with existing
 assertion rewriting

The code
```
x = 0
assert x == 1
```
will give the failure message 0 == 1, so it shouldn't be different as
part of an unroll
---
 testing/test_assertrewrite.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/testing/test_assertrewrite.py b/testing/test_assertrewrite.py
index c453fe57d..e819075b5 100644
--- a/testing/test_assertrewrite.py
+++ b/testing/test_assertrewrite.py
@@ -656,11 +656,11 @@ class TestAssertionRewrite(object):
         else:
             assert lines == ["assert 0 == 1\n +  where 1 = \\n{ \\n~ \\n}.a"]
 
-    def test_all_unroll(self):
+    def test_unroll_expression(self):
         def f():
             assert all(x == 1 for x in range(10))
 
-        assert "0 != 1" in getmsg(f)
+        assert "0 == 1" in getmsg(f)
 
     def test_custom_repr_non_ascii(self):
         def f():

From 58149459a59c7b7d2f34e7291482d74e39d8ad69 Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Thu, 9 May 2019 19:08:10 +0300
Subject: [PATCH 12/14] Mark visit_all as a private method

---
 src/_pytest/assertion/rewrite.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index 0e988a8f4..bb3d36a9c 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -965,7 +965,7 @@ warn_explicit(
         visit `ast.Call` nodes on Python3.5 and after
         """
         if isinstance(call.func, ast.Name) and call.func.id == "all":
-            return self.visit_all(call)
+            return self._visit_all(call)
         new_func, func_expl = self.visit(call.func)
         arg_expls = []
         new_args = []
@@ -989,7 +989,7 @@ warn_explicit(
         outer_expl = "%s\n{%s = %s\n}" % (res_expl, res_expl, expl)
         return res, outer_expl
 
-    def visit_all(self, call):
+    def _visit_all(self, call):
         """Special rewrite for the builtin all function, see #5602"""
         if not isinstance(call.args[0], (ast.GeneratorExp, ast.ListComp)):
             return

From 322a0f0a331494746c20a56f7776aec1f08d9240 Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Thu, 9 May 2019 19:12:58 +0300
Subject: [PATCH 13/14] Fix mention of issue #5062 in docstrings

---
 src/_pytest/assertion/rewrite.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index bb3d36a9c..5690e0e33 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -990,7 +990,7 @@ warn_explicit(
         return res, outer_expl
 
     def _visit_all(self, call):
-        """Special rewrite for the builtin all function, see #5602"""
+        """Special rewrite for the builtin all function, see #5062"""
         if not isinstance(call.args[0], (ast.GeneratorExp, ast.ListComp)):
             return
         gen_exp = call.args[0]

From 22d91a3c3a248761506a38fdf26c859b341e82be Mon Sep 17 00:00:00 2001
From: Tomer Keren <tomer.keren.dev@gmail.com>
Date: Sat, 18 May 2019 14:27:47 +0300
Subject: [PATCH 14/14] Unroll calls to all on python 2

---
 src/_pytest/assertion/rewrite.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/_pytest/assertion/rewrite.py b/src/_pytest/assertion/rewrite.py
index 5690e0e33..e3870d435 100644
--- a/src/_pytest/assertion/rewrite.py
+++ b/src/_pytest/assertion/rewrite.py
@@ -1020,6 +1020,8 @@ warn_explicit(
         """
         visit `ast.Call nodes on 3.4 and below`
         """
+        if isinstance(call.func, ast.Name) and call.func.id == "all":
+            return self._visit_all(call)
         new_func, func_expl = self.visit(call.func)
         arg_expls = []
         new_args = []