diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index d5917742..03888c8e 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -17,7 +17,7 @@ jobs:
       with:
         python-version: 3.8
     - name: Install dependencies
-      run: pip install 'isort==5.*' black
+      run: pip install -e .[dev]
     - name: Lint with isort
       run: isort --profile black --length-sort --line-width 120 -c .
     - name: Lint with black
@@ -34,7 +34,6 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: 3.8
-    # We don't need vivisect, so we can install capa using Python3
     - name: Install capa
       run: pip install -e .
     - name: Run rule linter
diff --git a/capa/features/__init__.py b/capa/features/__init__.py
index 1eee81b4..c88cd153 100644
--- a/capa/features/__init__.py
+++ b/capa/features/__init__.py
@@ -31,7 +31,7 @@ def bytes_to_str(b):
 
 
 def hex_string(h):
-    """ render hex string e.g. "0a40b1" as "0A 40 B1" """
+    """render hex string e.g. "0a40b1" as "0A 40 B1" """
     return " ".join(h[i : i + 2] for i in range(0, len(h), 2)).upper()
 
 
diff --git a/capa/features/extractors/ida/file.py b/capa/features/extractors/ida/file.py
index 5ca2370d..6f55ed45 100644
--- a/capa/features/extractors/ida/file.py
+++ b/capa/features/extractors/ida/file.py
@@ -78,7 +78,7 @@ def extract_file_embedded_pe():
 
 
 def extract_file_export_names():
-    """ extract function exports """
+    """extract function exports"""
     for (_, _, ea, name) in idautils.Entries():
         yield Export(name), ea
 
@@ -144,7 +144,7 @@ def extract_file_strings():
 
 
 def extract_features():
-    """ extract file features """
+    """extract file features"""
     for file_handler in FILE_HANDLERS:
         for feature, va in file_handler():
             yield feature, va
diff --git a/capa/features/extractors/ida/helpers.py b/capa/features/extractors/ida/helpers.py
index 8c62af58..4b7dcdeb 100644
--- a/capa/features/extractors/ida/helpers.py
+++ b/capa/features/extractors/ida/helpers.py
@@ -79,7 +79,7 @@ def get_segment_buffer(seg):
 
 
 def get_file_imports():
-    """ get file imports """
+    """get file imports"""
     imports = {}
 
     for idx in range(idaapi.get_import_module_qty()):
@@ -116,7 +116,7 @@ def get_instructions_in_range(start, end):
 
 
 def is_operand_equal(op1, op2):
-    """ compare two IDA op_t """
+    """compare two IDA op_t"""
     if op1.flags != op2.flags:
         return False
 
@@ -142,7 +142,7 @@ def is_operand_equal(op1, op2):
 
 
 def is_basic_block_equal(bb1, bb2):
-    """ compare two IDA BasicBlock """
+    """compare two IDA BasicBlock"""
     if bb1.start_ea != bb2.start_ea:
         return False
 
@@ -156,7 +156,7 @@ def is_basic_block_equal(bb1, bb2):
 
 
 def basic_block_size(bb):
-    """ calculate size of basic block """
+    """calculate size of basic block"""
     return bb.end_ea - bb.start_ea
 
 
@@ -174,7 +174,7 @@ def read_bytes_at(ea, count):
 
 
 def find_string_at(ea, min=4):
-    """ check if ASCII string exists at a given virtual address """
+    """check if ASCII string exists at a given virtual address"""
     found = idaapi.get_strlit_contents(ea, -1, idaapi.STRTYPE_C)
     if found and len(found) > min:
         try:
@@ -228,23 +228,23 @@ def get_op_phrase_info(op):
 
 
 def is_op_write(insn, op):
-    """ Check if an operand is written to (destination operand) """
+    """Check if an operand is written to (destination operand)"""
     return idaapi.has_cf_chg(insn.get_canon_feature(), op.n)
 
 
 def is_op_read(insn, op):
-    """ Check if an operand is read from (source operand) """
+    """Check if an operand is read from (source operand)"""
     return idaapi.has_cf_use(insn.get_canon_feature(), op.n)
 
 
 def is_op_offset(insn, op):
-    """ Check is an operand has been marked as an offset (by auto-analysis or manually) """
+    """Check is an operand has been marked as an offset (by auto-analysis or manually)"""
     flags = idaapi.get_flags(insn.ea)
     return ida_bytes.is_off(flags, op.n)
 
 
 def is_sp_modified(insn):
-    """ determine if instruction modifies SP, ESP, RSP """
+    """determine if instruction modifies SP, ESP, RSP"""
     for op in get_insn_ops(insn, target_ops=(idaapi.o_reg,)):
         if op.reg == idautils.procregs.sp.reg and is_op_write(insn, op):
             # register is stack and written
@@ -253,7 +253,7 @@ def is_sp_modified(insn):
 
 
 def is_bp_modified(insn):
-    """ check if instruction modifies BP, EBP, RBP """
+    """check if instruction modifies BP, EBP, RBP"""
     for op in get_insn_ops(insn, target_ops=(idaapi.o_reg,)):
         if op.reg == idautils.procregs.bp.reg and is_op_write(insn, op):
             # register is base and written
@@ -262,12 +262,12 @@ def is_bp_modified(insn):
 
 
 def is_frame_register(reg):
-    """ check if register is sp or bp """
+    """check if register is sp or bp"""
     return reg in (idautils.procregs.sp.reg, idautils.procregs.bp.reg)
 
 
 def get_insn_ops(insn, target_ops=()):
-    """ yield op_t for instruction, filter on type if specified """
+    """yield op_t for instruction, filter on type if specified"""
     for op in insn.ops:
         if op.type == idaapi.o_void:
             # avoid looping all 6 ops if only subset exists
@@ -278,7 +278,7 @@ def get_insn_ops(insn, target_ops=()):
 
 
 def is_op_stack_var(ea, index):
-    """ check if operand is a stack variable """
+    """check if operand is a stack variable"""
     return idaapi.is_stkvar(idaapi.get_flags(ea), index)
 
 
@@ -332,7 +332,7 @@ def is_basic_block_tight_loop(bb):
 
 
 def find_data_reference_from_insn(insn, max_depth=10):
-    """ search for data reference from instruction, return address of instruction if no reference exists """
+    """search for data reference from instruction, return address of instruction if no reference exists"""
     depth = 0
     ea = insn.ea
 
@@ -375,5 +375,5 @@ def get_function_blocks(f):
 
 
 def is_basic_block_return(bb):
-    """ check if basic block is return block """
+    """check if basic block is return block"""
     return bb.type == idaapi.fcb_ret
diff --git a/capa/features/extractors/ida/insn.py b/capa/features/extractors/ida/insn.py
index 3f5aef52..ec2f8070 100644
--- a/capa/features/extractors/ida/insn.py
+++ b/capa/features/extractors/ida/insn.py
@@ -53,7 +53,7 @@ def get_imports(ctx):
 
 
 def check_for_api_call(ctx, insn):
-    """ check instruction for API call """
+    """check instruction for API call"""
     if not insn.get_canon_mnem() in ("call", "jmp"):
         return
 
@@ -256,7 +256,7 @@ def bb_stack_cookie_registers(bb):
 
 
 def is_nzxor_stack_cookie_delta(f, bb, insn):
-    """ check if nzxor exists within stack cookie delta """
+    """check if nzxor exists within stack cookie delta"""
     # security cookie check should use SP or BP
     if not capa.features.extractors.ida.helpers.is_frame_register(insn.Op2.reg):
         return False
@@ -279,7 +279,7 @@ def is_nzxor_stack_cookie_delta(f, bb, insn):
 
 
 def is_nzxor_stack_cookie(f, bb, insn):
-    """ check if nzxor is related to stack cookie """
+    """check if nzxor is related to stack cookie"""
     if contains_stack_cookie_keywords(idaapi.get_cmt(insn.ea, False)):
         # Example:
         #   xor     ecx, ebp        ; StackCookie
diff --git a/capa/features/extractors/smda/basicblock.py b/capa/features/extractors/smda/basicblock.py
index 07477139..98b91ec3 100644
--- a/capa/features/extractors/smda/basicblock.py
+++ b/capa/features/extractors/smda/basicblock.py
@@ -15,7 +15,7 @@ def _bb_has_tight_loop(f, bb):
 
 
 def extract_bb_tight_loop(f, bb):
-    """ check basic block for tight loop indicators """
+    """check basic block for tight loop indicators"""
     if _bb_has_tight_loop(f, bb):
         yield Characteristic("tight loop"), bb.offset
 
@@ -39,7 +39,7 @@ def get_operands(smda_ins):
 
 
 def extract_stackstring(f, bb):
-    """ check basic block for stackstring indicators """
+    """check basic block for stackstring indicators"""
     if _bb_has_stackstring(f, bb):
         yield Characteristic("stack string"), bb.offset
 
diff --git a/capa/features/extractors/smda/insn.py b/capa/features/extractors/smda/insn.py
index bf23f607..48ef4c1c 100644
--- a/capa/features/extractors/smda/insn.py
+++ b/capa/features/extractors/smda/insn.py
@@ -293,7 +293,7 @@ def extract_insn_peb_access_characteristic_features(f, bb, insn):
 
 
 def extract_insn_segment_access_features(f, bb, insn):
-    """ parse the instruction for access to fs or gs """
+    """parse the instruction for access to fs or gs"""
     operands = [o.strip() for o in insn.operands.split(",")]
     for operand in operands:
         if "fs:" in operand:
diff --git a/capa/features/extractors/viv/basicblock.py b/capa/features/extractors/viv/basicblock.py
index 76ffefe6..a76aa179 100644
--- a/capa/features/extractors/viv/basicblock.py
+++ b/capa/features/extractors/viv/basicblock.py
@@ -45,7 +45,7 @@ def _bb_has_tight_loop(f, bb):
 
 
 def extract_bb_tight_loop(f, bb):
-    """ check basic block for tight loop indicators """
+    """check basic block for tight loop indicators"""
     if _bb_has_tight_loop(f, bb):
         yield Characteristic("tight loop"), bb.va
 
@@ -68,7 +68,7 @@ def _bb_has_stackstring(f, bb):
 
 
 def extract_stackstring(f, bb):
-    """ check basic block for stackstring indicators """
+    """check basic block for stackstring indicators"""
     if _bb_has_stackstring(f, bb):
         yield Characteristic("stack string"), bb.va
 
diff --git a/capa/features/extractors/viv/insn.py b/capa/features/extractors/viv/insn.py
index 6321fcab..42deee51 100644
--- a/capa/features/extractors/viv/insn.py
+++ b/capa/features/extractors/viv/insn.py
@@ -476,7 +476,7 @@ def extract_insn_peb_access_characteristic_features(f, bb, insn):
 
 
 def extract_insn_segment_access_features(f, bb, insn):
-    """ parse the instruction for access to fs or gs """
+    """parse the instruction for access to fs or gs"""
     prefix = insn.getPrefixName()
 
     if prefix == "fs":
diff --git a/capa/ida/helpers/__init__.py b/capa/ida/helpers/__init__.py
index 17744ebb..41e4b463 100644
--- a/capa/ida/helpers/__init__.py
+++ b/capa/ida/helpers/__init__.py
@@ -71,7 +71,7 @@ def get_disasm_line(va):
 
 
 def is_func_start(ea):
-    """ check if function stat exists at virtual address """
+    """check if function stat exists at virtual address"""
     f = idaapi.get_func(ea)
     return f and f.start_ea == ea
 
diff --git a/capa/ida/plugin/item.py b/capa/ida/plugin/item.py
index e6f4d436..77db0c32 100644
--- a/capa/ida/plugin/item.py
+++ b/capa/ida/plugin/item.py
@@ -202,7 +202,7 @@ class CapaExplorerRuleMatchItem(CapaExplorerDataItem):
 
     @property
     def source(self):
-        """ return rule contents for display """
+        """return rule contents for display"""
         return self._source
 
 
diff --git a/setup.py b/setup.py
index a6e47bac..580a3be1 100644
--- a/setup.py
+++ b/setup.py
@@ -70,7 +70,7 @@ setuptools.setup(
             "pytest-instafail==0.4.2",
             "pytest-cov==2.11.1",
             "pycodestyle==2.7.0",
-            "black==20.8b1",
+            "black==21.4b0",
             "isort==5.8.0",
         ]
     },